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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Mains AC source Unicum. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Power Supplies A radio amateur usually has various AC transformers on the farm. All of them, as a rule, are of different power, with different sets of voltages. When you think about connecting a new device, it turns out that everything that is available is no good. LATR can help out, but not everyone has it, and you won’t constantly power the device from LATR. I have implemented this idea. Rewind the transformer of the largest capacity (from the ones you have) so as to make eight secondary windings. The first winding is designed for an output voltage of 1 V, the second - for 2 V, the third - for 4 V, and then with each new winding the voltage doubles. On the last eighth winding, the output voltage is 128 V. The circuit diagram of the transformer (I called it "Unicum") is shown in Fig. 1, a. Solder the outputs of the secondary windings to the contacts of the X1 socket type RP1416, which is a blade connector with improved characteristics (powered) and is suitable for switching power circuits with currents up to 6 A. Both the socket and the RP14 plug have greater mechanical strength (they were used in the old lamp equipment, where the filament currents are large enough). The conclusions of each of the windings must be soldered to their own pair of contacts of the X1 RP14-16 socket (Fig. 1, b): the first winding - to 1a and 1b; the second winding - on 2a and 2b, ..., the eighth winding - on 8a and 8b. In this case, you need to make sure that the beginnings of the windings are connected to the contacts "a", and the ends - to the contacts "b". In Fig. 1, a, the highest-voltage secondary winding is shown at the top of the circuit, the lowest-voltage - at the bottom. This is a violation of the ESKD, but it was allowed for the reason that the eighth winding is soldered to contacts 8a and 8b, which are located near the two bevels of the X1 socket (mnemonically showing the direction of increasing the voltage of the windings).
The overall power of the transformer can be anything, but with the selected connector RP14, the current should not exceed 6 A, so the overall power of the transformer cannot exceed 1,5 kW. Such a transformer is not yet too large for domestic use, besides, the rated current for which mains sockets and switches are designed is also 6 A. The use of a transformer of this power will practically solve all problems in everyday life, a workshop, a laboratory. For example, through it you can turn on household appliances with a mains voltage that differs from our standard (for example, 240, 127, 110 V, etc.). You can, for example, connect a wide variety of soldering irons (for voltages of 24, 36, 42 V) and others, and there are soldering irons with underheating and overheating (you can accurately select the desired voltage). Table 1 provides information for the manufacture of transformers with power from 200 to 1600 W (four options). Table 1
The transformer can be made on rod cores of common sizes. For example, for the 200 W option, the core from the TS-200 (or TS-180) SL 24x45 television transformer is suitable, and for the 400 W option, the TS-360 (TS-330) SL 25x50. The convenience of the table lies in the fact that an integer number of winding turns per 1 V of the output voltage is obtained (5, 4, 3, 2 turns for powers of 200, 400, 800 and 1600 W, respectively). In addition, all secondary windings can be made with a wire of the same diameter, which makes it possible to simplify the winding technology, ensure optimal thermal conditions and use one fuse for the total output voltage. Figure 2 shows the recommended version of the Unicum transformer housing. It seems optimal to me to place the transformer on the floor. Therefore, the X1 socket is installed on the upper plane of the housing, there is also a handle for carrying the transformer. All bao steel elements (switch S switch on indicator HL1, fuse FU1 and power cord input) are installed on a vertical front panel.
It is desirable to provide the case with elastic (rubber) legs for stability. Now let's move on to desoldering the RP14 plug to obtain any voltage from 1 to 255 V in increments of 1 V. As can be seen from Fig. 1, voltages 1, 2, 4, 8, 16, 32, 64 and 128 V can be obtained from one of the selected windings by connecting to the contacts "a" and "b" of the corresponding row. This option is shown in Fig. 3a for an output voltage of 4 V. The maximum voltage of 255 V is obtained by connecting all eight secondary windings in series. At the same time, inclined jumpers are installed on the RP14 plug (1b-2a, 2b-3a, 3b-4a, ..., 7b-8a), and the voltage of 255 V is removed from contacts 1a and 8b.
All other options for obtaining voltages are formed by calculating the binary code of the selected voltage. For example, a voltage of 13 V is obtained by summing the voltages of the 1st, 3rd and 4th windings, since 13 \u8d 4 + 1 + 3. As can be seen from Fig. 1b, the jumper bypasses the unnecessary second winding (connects 3b and 27a), a voltage of 1 V is obtained by summing the voltages of the 2st, 4nd, 5th and 27th windings, since 16 \u8d 2 + 1 + 3 + 36. As can be seen from Fig. 3, the jumper bypasses the unnecessary third winding, a voltage of 6 V is obtained by summing the voltages of the 36rd and 32th windings (4 \u3d XNUMX + XNUMX), the jumper connects (Fig. XNUMX, d) the end of the third and the beginning of the sixth windings. To obtain standard voltages of 42, 48, 60, 75, 110, 127, 220 and 240 V, the jumper configuration is shown in Fig. 3, l...n, respectively. The conclusions shown in Fig. 3 by arrows are output and form a cable. Since the output voltage of the cable can be life-threatening, the plug leads after desoldering the output cable should be carefully insulated (preferably with a cover or cap). Switching to a new voltage requires several minutes of soldering the leads. But, if someone is too lazy to do this and he has eight toggle switches for a working current of at least 6 A, then we can recommend the circuit in Fig. 4, in which, with the left position of the toggle switch, the corresponding winding is included in the winding chain, with the right - disabled. Then the transition to the required voltage consists in converting this voltage into a binary code and setting this binary code with toggle switches. To switch to a binary code, you should remember the powers of the number 2: 20 = 1; 21 = 2; 22 = 4; 23 = 8; 24 = 16; 25 = 32; 26 = 64; 27 = 128. Now, from the desired voltage (for example, 167 V), we subtract the largest number from this series (but less than the required one) 167 - 128 = 39, repeat this procedure 39 - 32 = 7 and then 7 - 4 = 3; 3 - 2 = 1 and 1 - 1 = 0. From the given number, we subtracted the numbers 27, 25, 22, 21, 20.
Therefore, in these digits of the binary code there will be "1", in the rest zeros: 10100111. Accordingly, in the circuit (Fig. 4) toggle switches with numbers SA8, 5.sir4. cirSA6, SA3, SA2 turn to the left position, the rest to the right, and we will get the required voltage of 167 V. If we use toggle switches of the P1T type or their foreign analogue KNX-1 (3 A, 250 V), we will get a convenient implementation of a programmable chip. Since the distance between the extreme terminals of the toggle switch is approximately equal to the distance between rows a and b of RP14-16, and the width of this type of toggle switches is approximately equal to the pitch of the connector contacts in the rows, a very compact installation of the SA1SA8 toggle switch block directly onto the contacts of the RP14-16 knives is possible (Fig. 4 ). However, such a chip on microtoggle switches is expensive, so Figure 5 shows a cheaper version of the implementation of a programmable chip for operational connection with programming on jumpers. For quick connection, excess jumpers are soldered and, to obtain a given voltage, the extra jumpers are simply bitten out, and where the jumper is bitten out in row "a", the jumper in row "b" is preserved and vice versa. Figure 5 shows which jumpers are bitten out and which ones are kept for the given example at 167 V.
The use of programmable chips is convenient because any device with a supply voltage from 1 to 255 V is connected to the same socket of the X1 transformer, and the chip automatically "remembers" the supply voltage needed for the device. When placing the transformer on the floor near the desktop, a toggle switch panel can be placed on the table itself (Fig. 6). It is desirable to assemble it on toggle switches of the TP12 type and connect it to the transformer with a 16-core cable.
Fig. 7 shows two variants of the circuit diagram of such a console, and the variant of Fig. 7, b corresponds to the wiring diagram of Fig. 4. The circuit in Fig. 7, a is a simplified version of the remote control implementation and differs in that the windings that are not involved in obtaining the output voltage are completely turned off. Sometimes this is required to reduce the level of interference from unused windings. In addition, this scheme is extremely simple installation.
Wiring diagrams Fig. 8, a, b fully correspond to the electrical circuits Fig. 7.
In conclusion, a few words about safety regulations. In industry, protective grounding and zeroing of devices are used. Our household network is not very safe due to the fact that the plug used is symmetrical and it is not known where the ground is and where the phase of the mains voltage is. Therefore, household appliances are not grounded, and dangerous voltages can occur in the appliance case. These voltages can also arise due to the fact that there are leakage currents and seepage through parasitic capacitances at transformer substations. The use of the "Unicum" transformer, due to galvanic isolation from the network, makes it possible to avoid dangerous voltages, i.e. the appliance being used can be earthed. If you firmly decided to repeat such a source, made a universal transformer, as well as a universal toggle switch, then you were convinced of the exceptional convenience of the system. You have at your disposal a truly unique source of alternating current. Any voltage in the range from 1 to 255 V is now at your fingertips, i.e. you can quickly get any in a matter of seconds and conduct an experimental or operational connection of almost any 50 Hz AC load. But often there is a need to smoothly change the voltage across the load. Usually LATR is used for this, but it is not safe. So far, we had at our disposal a toggle switch - a very convenient product, and with its help you can change the voltage in steps of 1 V, but practical manipulations with the toggle switches are very difficult when sorting through the binary code, although they can be performed very quickly with skills. I propose to supplement the "Unicum" system with a device - a mechanical machine for a smooth (with a step of 1 V) set of voltages 1-2-4-8-16-32-64-128 V from the "Unicum" universal transformer. The product is quite possible to implement at home with minimal use of turning. This is a purely mechanical device (more precisely, electromechanical). The output voltage is changed by turning the knob by 16 V / 1 turn, and turning the knob clockwise increases the voltage, and turning it counterclockwise decreases it. The product is easy to upgrade: instead of a handle, you can install an electric drive (an electric motor with a gearbox), and control it with a "balaxir" type switch (for reversing the electric motor). The installation of the electric drive is provided for by the design (Fig. 9) and will not require alteration of the design with a manual drive, the description of which is proposed below.
The proposed product is a drum programmable (or coded) switch with 256 positions. The actual electrical switching of voltages from the transformer windings is carried out by eight microswitches SA1-SA8 (Fig. 10). The switching circuit is identical to that used in the design of the toggle switch panel and the programmable plug on the toggle switches described earlier, but they are switched by software, mechanically (by pressing the corresponding pushers of the microswitches).
To simplify the implementation, the switches are divided into two groups (blocks): the SA1-SA4 block is designed for switching voltages of 1, 2, 4 and 8 V, respectively, and the SA5-SA8 block is for switching voltages of 16, 32, 64 and 128 V, respectively. Structurally, in the proposed implementation, microswitches of the MIZ type (3A, 250 V) are used, assembled in two identical blocks of 4 pcs. with a step of 10 mm using textolite type-setting gaskets and two steel L-shaped brackets for installation on the base plane. The blocks are tightened with 4 studs (or screws) with an M2,5 thread, 40 mm long. The entire electrical circuit (including the FU1 fuse, XT1 and XT2 output sockets and cable entry, reinforced at the other end with a RP14-16 plug) is mounted on a mounting base - a getinax plate 8-12 mm thick on 4 rubber legs ( caps from medical vials). The mechanical part is built on the principle of a drum programmable switch. Moreover, two completely identical programmable drums are used. The drum is a mechanical unit for converting rotational movement into microswitch pushers by means of copiers on cams (protrusions) and switching off on depressions. In fact, the drum is a monolithic assembly of four programmable disks and additional elements (ratchet and shaft mounts). Each disc is a strip on the surface of the drum with a specific distribution of cams and troughs. It is designed to generate control mechanical actions for one switch. The law of formation of cams and troughs is the program. And the process of manufacturing (forming) a sequence of depressions and recesses on the disks is by programming. On each of the drums there are four disks with programming according to the binary code law (Fig. 11). The lower disk contains the program for switching the low order switch 1 and contains 8 cams and 8 cavities evenly distributed around the circumference; the disk second from the bottom contains four cams and four cavities, evenly distributed around the circumference, and is designed to control the weight category 2 of the binary code; the third disk from the bottom contains the program for controlling the switch of weight category 4 and contains 2 cams and 2 cavities evenly distributed around the circumference. And finally, the upper disk contains the program for controlling switching by the highest weight category 8 and contains one cam on half of the circle and a cavity on the other half of the circle. The mutual placement of the cams of the discs at the angles of rotation is strictly defined and corresponds to the development of the drum shown in Fig. 11 (left), for the correct formation of the binary code on the line of copiers, and with the right rotation of the drum, the code increases, and with the left it decreases.
Let's consider the electrical part for practical recommendations in order to further focus on fine mechanics, since the electrical circuit can only be mounted after the execution of the mechanical part, but the blanks of the nodes must be available immediately. For switch blocks, the recommendations are as follows: the recommended step between the pushers MI3 = 10 mm. With a thickness of switches of 7 mm, this will allow using gaskets to accurately install them with the desired pitch and isolate them from each other (especially the terminals), while (before assembly) the side surfaces should be rubbed on the abrasive plane to avoid damage and jamming (grind relief inscriptions, technological influxes and other irregularities) when tightening the studs. They should be installed so that all four pushers are strictly in line and equally protrude above the switch block (you may have to select microswitches that are identical to each other for each block, in any case, the type should be the same). A variety of MI3-B switches with a "ski" type leash is produced, which at first glance is completely suitable for this implementation and simplifies the mechanical part, but the mechanical fastening and accuracy of such leashes as cam disk copiers are less reliable. In addition, it is undesirable to use MI3B in the version in which, when the leash is pressed, the pusher is pressed, since in the event of a breakdown, such a switch will remain in the on position, which is undesirable for safety reasons. The height of the bent legs of the L-shaped brackets is 10 mm for the convenience of electrical installation and assembly of blocks with studs outside the bending zone. According to this recommendation, the height of the blocks (without pushers) should be exactly 30 mm, and the gap between the base and the bottom of the block should be 10 mm (to pass the wiring wires). The "paws" of the blocks of two L-shaped brackets should form a plane. When debugging, the height of the blocks can be adjusted by placing getinax spacers between the plane of the "paws" of the blocks and the base. The final position of the pusher lines is also clarified in the process of debugging together with the mechanical part from the condition of a clear switching and selection of backlashes in the gear drum - copy - switch pusher. The final fastening of the blocks is carried out with 4 M3 screws (two per foot) to the base. For debugging, I recommend assembling a debugger attachment (Fig. 12) on 8 light bulbs and a RL14-16 socket. Before debugging, the assembled switch blocks (but not fixed) are connected to an electrical circuit. The cable plug is connected from the debugger socket, and the external voltage (direct or alternating current) rated for incandescent lamps, for example 6,3 V, is supplied from an external PSU or transformer to the common wire of the bulbs (wire "C") and socket contacts (row "a ", wire "d"), and also (to indicate the inclusion of SA8) wire "d" should be connected to "with" terminal XT1.
When the pusher of the corresponding switch is pressed, the corresponding debugger lamp should light up. The proposed debugger can serve as a regular tester of products of the "Unicum" series to check the programmed chips, the serviceability and condition of toggle switches and other products during manufacture and operation, if the wires "c", "d" are reinforced with a chip based on the RP14-16 plug with a programmed nominal lamp voltage (no more than 36 V, for safety). Only after checking the switching circuit by the debugger can it be stated that the product complies with the Unicum standard, works correctly and accurately. Instrument sockets XT1 and XT2 for easy connection of loads and installation in mech. the machines should be mounted on a getinax plate 3 ... 4 mm thick (the size is specified during layout) with a distance in the axes of the nests of 29 mm, and the plate should be finally fixed at the front edge of the base at the corners. Similarly, at the rear edge of the base, fix the holder of the fuse-link FU1 type DPB, DPV or the like. The input cable from the transformer (16 cores with a cross section of 1 mm2 of total insulation) is fixed at the rear edge of the base with a steel clamp (bracket). The first drum receives rotation directly from the handle or a low-voltage electric drive, and the second one rotates 16 times slower than the first and receives rotation through a spur gear from the shaft of the first drum. Thus, it turns out that the disk of the least significant digit on drum II switches the weight digit 16, and the rest, respectively, 32 (2 on the first drum), 64 (4) and 128 (8). For ease of implementation, the gear transmission is performed in two stages. Firstly, this reduces the size of the gearbox (a large gear for a gear ratio of 1/16 is too large in diameter), and secondly, we get the rotation of both drums in the same direction, which actually made it possible to make exactly the same drums. A gear ratio of 1/16 is obtained by connecting identical gears in series on gears with a ratio of the number of teeth (gear ratio) of 1/4. We fix a block of two intermediate gears on an intermediate axle or shaft in the middle between the axes of the main shafts with drums I and II. Accordingly, drum I switches the block of switches SA1-SA4, and drum II - the block of switches SA5-SA8. Since the programmable drum is a cyclic source of code with an infinite sweep, the restriction of enumeration cycles is applied due to the undesirability of the code jump from 255 to 0 when increasing, and especially from 0 to 255 (because these will be voltages!) When the cycle is repeated. Therefore, on the second drum, we set the limiter stop (due to the actual dimensions of the pin and screw, one position in the code will have to be sacrificed either "0" or "255" in the name of the same security). And to save the mechanism (the moment on the II shaft is 16 times greater than the torque on the I and can easily crush the emphasis), the transmission of rotation to the first shaft is carried out by means of a torque limiting clutch (if it is exceeded, it will begin to slip). What is indicated in Fig. 11 as positions practically means the position of the line of copiers (cams at the turns of the switches). The copiers track the relief of the disks and, through levers, transfer forces to the pushers of the switches. The positions show the stable position of the copier line, in contrast to the markup in degrees, and are shifted relative to it by 11°15' (half the angular step of the drum). For a clear fixation of the position of the drum I in the positions of the copiers on the drum I, we install a ratchet (a ball lock similar to those used in the construction of biscuit switches), and on the right edge of the drum we drill 16 conical holes evenly distributed around the circumference. A ratchet is also needed so that the handle (handle) and other mass imbalances cannot move the drum spontaneously from the set position of the code. The same recesses are made on the second drum, where you can also install a ratchet, but already paired with a special clutch that provides an abrupt movement of the second drum. This is a hard-to-implement node, and therefore I did not use it, but if there are difficulties with debugging, then such a node can be introduced into the design. The main difficulty lies in the fact that it is necessary to perform precise smooth transitions from the cams to the troughs especially and especially accurately they should be performed on the second drum. The positions of the ratchet and stop on the drawings are shown conditionally, they must be clarified during debugging. Both drums on the shafts should be fixed in exactly the same way (in position "0" strictly vertically down on the copier line). It is desirable to use the main gear train on different gears (backlash-free). In addition to the main gear, there is an auxiliary one - to the counter. Its gear ratio (total) should be 1,6 (16/10 or 5/8), i.e. the shaft of the drum counter (for example, from a tape recorder) must rotate 1,6 times faster than the shaft I of the machine and change its readings by 16 units in one revolution of the shaft I. The number of gears in the transmission is not limited and can be either even (for counters of left rotation - the numbers pop up from below) or odd. The use of a rubber belt is undesirable, since the counter must be installed once after debugging, and the reset button is removed. But for the transmission of rotation from the electric drive, the use of a belt drive is desirable, since elastic deformations and slips will provide pseudo-jump rotation of the shaft I, limit the maximum torque from the drive and compensate for the inertia of the drive. The torque limiting clutch itself is a block of two disks: a drive disk driven by a handle or a pulley, put on shaft I, and a driven disk rigidly fixed to shaft I with a conical recess for the ball. The ball is installed on the handle with the clutch closed in one specific position to determine the voltage by the position of the handle within the 1st revolution of the I drum. When the torque from the drive of a certain value (on the end stop) is exceeded, the ball is pushed out of the recess of the driven disk and rolled over its surface. To select the wear of the disks during operation, the drive disk is additionally spring-loaded from the end (the spring is between the lock washer and the end face of the disk sleeve). A blind nut (cap) is screwed onto the sleeve (cylindrical part) of the drive disk to close the lock washer, and in the version with a manual drive, a handle bar is fixed on it. The stop unit is a D4 mm pin on the II drum and an M5 stop screw on the cheek of the fixed part of the mechanism. Shafts (main) have diameters of 6 mm. Drums, disks and gears are fixed on M3 screws (2 each at an angle of 90 ° relative to each other). Instead of one screw, you can use a pin in the holes drilled after debugging (carefully hammer in). So more reliable. Drum blanks are best turned on a lathe from bronze (it works well and wears slowly) or hard aluminum alloy (duralumin), but can be turned from hard plastics, such as ebonite or hard polyethylene (even easier to process and has little friction at the ends ). To ensure accurate rotation, the drum shafts are installed in bearings No. 35-26 (for D6 mm shafts). Bearings, machined from steel, are pressed into holders for mounting on a plane (faceplates). The intermediate gears of the main gear can be mounted on an axle (short or long for rigidity without bearings) or on a freely rotating countershaft in bearings (a better but more expensive solution). The entire mechanical part is a monoblock made of steel 1,5 mm thick between two cheeks. The distance (60 mm for drums 57 mm wide) between the cheeks is fixed with two spacer prisms - plane-parallel bars made of steel 60x45x8 mm with threaded holes M3 from the ends (2 each from the end, Fig. 13 and 14). The cheeks of the mechanical block have 10 mm bends at the lower (paw) and upper (platform for the electric drive or fastening of the housing cover with M3 nuts fixed from below) fastenings. These bends and spacer prisms provide rigidity and geometric stability of the structure. In the upper front part (Fig. 13 and 14), the cheeks are cut at an angle of 45 ° for convenient installation of a mechanical counter (mainly for the convenience of taking readings from the drum).
Holes in the cheeks must be drilled together (after marking, they should be temporarily tightened with screws), which reduces the likelihood of distortions and misalignment of the shafts and axes. The copier blocks mentioned earlier are made of a 4,5 mm wide brass strip, which wraps around the sleeve and is soldered to a plate of double-sided foil fiberglass (for rigidity and weight reduction). A spring is fixed in the upper part (sections of the winding spring from the alarm clock) and cams (copiers) are formed. The upper front part of the copiers (to the left of the cams) (Fig. 15) is not immediately soldered to the insert foil, but blocks of four copiers are assembled on the axis of the D3 mm copiers and a line is set along the copiers, as well as the same height and bending angles. The corners of the copier should be somewhat "sharper" than the transitions on the disks of the drums for the copiers to clearly follow the relief of the disk, but smooth enough to eliminate mechanical shocks and deformation of the copiers.
Finally, the copier blocks are mounted in the lower part on the axles using spacer bushings and washers (the set for forming the pitch corresponds to the pitch of the disks). Copiers are spring-loaded by installing an additional axis-stop. This solution allows you to debug the mechanical part separately from the electrical one, for example, in positions "0" and "255" all copiers should form a plane with their lower surfaces. After debugging the mechanical part, switch blocks are substituted under the drums (as described at the beginning) and joint final assembly, verification and debugging are carried out using an electrical debugger. The entire structure is covered with a plastic cover (glued, for example, from a vegetable box from the refrigerator), which is fixed with four M3 screws from above (in the manual version). It has appropriate cutouts for access to the sockets, fuse, cable entry, meter window and hole for installing the handle. In the version with an electric drive, the handle is not installed, and the body is made higher (for an electric drive). The electric motor control balancer is also fixed in the upper volume at the drive. An AC drive, for example, with an electric motor D32-P1 is connected as follows: the winding of the 127 V electric motor through C \u1d 128 micron is connected to a voltage of 8 V (terminals 8a and 14v RP16-12), and the 4 V winding is connected to terminals 4a and 8v , 16v (16v is possible through the "Reverse" switch). Thus, the electric drive does not require additional voltage. For particularly accurate operation with an electric drive, a ratchet-controlled limit switch can be installed at XNUMX positions I of the shaft. It's a little more difficult. The Unicum secondary AC power supply based on a universal transformer allows not only to receive, but also to conveniently distribute the received voltages among current consumers, i.e. create a local distribution network, and a safe one, which is especially important for conditions of high humidity. In principle, it is possible to create a local network (in the house, workshop, garage, etc.) for any voltage up to 255 V. By creating a local network, we are, as it were, transforming our network standard (~ 220 V, 50 Hz, plug with D4 mm round pins) into some other with a frequency of 50 Hz, for example, European (220 (230) V, plug with D5 round pins mm and earthing), Korean (110/220 V, flat pin plug), etc. Apparently, the "European standard" is of the greatest interest for creating a safe network, since the cord, plug and socket have a grounding conductor connected to the body of the device. A lot of household electrical appliances and tools have recently appeared, and mostly with a "Euro plug". A simple replacement of a domestic socket or fine-tuning the "Euro plug" (thick pin) only reduces the safety of using electrical appliances in the domestic network, since it is necessary to abandon the grounding of the device case. A full-fledged safe connection in our network is possible only through an isolating transformer of such devices with a ground loop device. Of course, it is unprofitable to supply each device with an isolation transformer, but grounding can and should be installed. Moreover, when the device is powered through a low-power isolating transformer, the requirements for grounding (<4 Ohm) are somewhat reduced and natural grounding conductors such as water pipes are used (by the way, the water supply system is grounded and the bath should be grounded - there is even a strip or a screw) or heating fittings. More important, perhaps, is the equalization of potentials (induced and static) of instrument cases and surrounding electrically conductive objects (including pipelines and instruments, heating, plumbing, sewerage, floors, walls). Here I offer a multi-socket (8 pcs.) Distributor in the Euro standard, where the instrument cases are connected to each other and grounded. In addition, there are surge filters and fuses, and it can also be supplemented with modern "bells and whistles" such as varistor surge absorbers, etc. Let's distribute the voltage from the Unicum transformer obtained by means of a programmable chip (usually 220 V, but others are possible, for example, 110, 127, 240 V, etc.)). It makes sense to make several such distributors for different standards (sockets and voltages) as needed. Inductors L2-L9 are K22x16x5 ferrite rings, on which 30 turns of MGSHV 0,75 wire are wound into two wires, while the beginnings of the windings are connected to the voltage line, and the ends are connected to sockets. As a general (input) filter, it is best to use a ready-made filter, for example, from a TV with a switching power supply (C1, L1, C2, C3). To work with a 400 W transformer, 1 A fuses FU2 and FU3 are required. Having somewhat complicated the distributor, it is good to introduce control, i.e. switching loads on the voltage line. In practice, this is convenient, because it saves valuable time and makes work more convenient (with any electrical appliances). Who does not know the "concerns" with the search for the right plug, from dozens that come to hand, and the constant shortage of sockets with all these tees and extension cords. At the same time, it always (ironically) turns out that the plug of the necessary (right now) device is not plugged into the outlet, but many unnecessary ones are included, and among them there is always a plug from the device that you need to turn on in a minute, that's it, it will be pulled out and discarded away (so that it would be more fun to search, and the whole process became protracted and ridiculous). I propose to insert at least eight plugs of the most frequently turned on electrical appliances into the proposed distributor, turn on the mains switches on the devices, and control their switching on from a small remote control on the table (it will hardly take up space, I got 200x35x25 mm). At the same time, the distributor itself can be located on the floor or on the wall, and all the cords will not be confused and “loom” before your eyes. See fig. 16 for how it might look, and fig. 17 for how easy it can be. It is only necessary to find sufficiently reliable relays in the amount of 8 pcs. I recommend REN34 - small-sized and capable of switching alternating current 2 A at a voltage of 250 V.
In general, it should be agreed for the future that the relays consume a current of no more than 150 mA (trip current) and have a response voltage in the range of 10-15 V, i.e. working ~ 20 V. It is this voltage that will be obtained from an alternating 16 V, which is convenient to take from the 5th winding of a universal transformer, i.e. from terminals 5a and 5b RP14-16 (X1), straighten it (VD1-VD4, C4, Fig. 17) and switch from the control panel to the relay windings. The fact that we will use the 5th winding to power the control circuit does not mean at all that it should be bypassed when setting the main voltage. It is only important that the power circuits no longer have a connection with the control circuit, and for this the remote control does not have metal parts on its surface connected, for example, with a common wire with a button.
True, an extreme case is possible when the 5th winding, included in the main voltage circuit, suddenly breaks, then, indeed (if a load is connected), the control circuit will be under increased voltage, but this is already a malfunction. For such a case, the 16 V winding is connected to the rectifier of the control circuit through the 3 A fuse FU1, and a protective zener diode is installed in parallel with the capacitor C4 for a voltage greater than normal and safe for the remaining elements of the control circuit (C4, LEDs). In this case, I set the D816V to 35 V. Then, when an increased voltage appears on the control circuit instead of 16 V, it will rise to 35-38 V, after which the zener diode will break through and the FU3 fuse will burn out. The main voltage is also connected through two fuses FU1 and FU2 to minimize losses in experimental situations. LEDs for indicating the inclusion of sockets, together with current-limiting resistors (HL1-HL8, R1-R8) and self-induction back EMF damping diodes VD6-VD13, are connected in parallel with the relay windings. I connected the free outputs of the relay windings to the socket of a new connector, for which I recommend RG1N-5-9 for 16 pins for connecting to the control panel with a flexible (so far 10-core) cable 1500 mm long. The control panel (miniature) can also be mounted on the distributor itself (on the box with common nodes, where "Unicum" is written, Fig. 16), as a control implementation option, but remote control is more convenient. In addition to the eight main latching switches, for example PD1, the console is equipped with a common switch SA9, which turns on or off the entire set of sockets (devices included in them) switched on by switches SA1-SA8. SA9 should be somewhat more powerful, for example, type P1T, and different from the rest. Turning on the remote control switch SA9, i.e. power supply to the control circuit (in this case, the simplest one) is indicated by the HL9 LED. The control panel is made in a suitable box (260x35x25 mm on the listed elements, but it can be much smaller). The distributor itself, when using standard sockets for open installation (60x60 mm), is mounted on a board (made of wood, furniture chipboard, textolite, etc.) with dimensions of 90x590 mm and a thickness of 8-25 mm. In the strip along the sockets with a width of 30 mm, there are relays K1-K8 and elements mounted on them, as well as filters L2-L9 (if they do not fit in the sockets). They are closed with an L- or U-shaped cover with holes for LED lenses (or window-light filters with numbers). Common components of the distributor: rectifier, input filter, fuses, control connector, ground terminal are mounted in a separate box (90x100x45 mm) on the edge of the board (Fig. 16). To install the distributor on the wall, on the reverse side of the base board, there are planks with holes for hanging on the nail heads with corresponding recesses for them. I think that the astute reader, experienced in radio electronics, has noticed that the Unicum source is not so simple and hides new possibilities that are associated with digital control. And this is true, and in order to realize these opportunities, you should move to a new level of source control. Partially, the idea of low-current control is considered on the example of a multi-socket distributor, where the "Unicum II" remote control and the power supply of the control circuit from one of the windings of the universal transformer (5th, ~6 V) are proposed. Having repeated the circuit of a multi-socket distributor, but having connected the contact groups of the relay according to the switching circuit of the transformer windings, which was previously used in tumbler structures and a mechanical machine, we will obtain a transitional relay unit (Fig. 18). Now it is not necessary to enter all voltages into the new remote control, but it is enough to connect 10 wires in a flexible cable (8 pcs. for current up to 150 mA and 2 pcs. 2-4 wires each to supply power to the control panel - so far for one HL9 LED on + 20 V, 1-2 wires are enough, and for a possible current selection up to 1 A and maintaining the flexibility of a cable with wires of the same cross section of about 0,1 mm2 - 16 wires) and reinforce with a RSH2 chip for 16 contacts (X2 in Fig. 18 and beyond).
I offer a simple and understandable wiring of the connector contacts, i.e. we solder the wires for switching the relay windings to a common wire from the K1-K8 relay in one row, starting from No. 1 and to contact No. 8, respectively, and for the common wire (-) and +20 V power, we take two contacts at the edges of the second row and leave four free contacts in the middle of the second row No. 11, 12, 13, 14, which we do not solder now, but will be used in the future. The RSh2 connector is a solid domestic connector and is often found in radio receivers. Of course, you can use any foreign connector, but I don’t think that modern stamped connectors are more reliable. The same applies to the previously proposed level 1 connector RP14. The power wires of the first level from the X1 connector of the RP14 type can be shortened (these wires were 18 m (16 x 1,1) in the toggle switch panel and a mechanical typewriter)! And all of them, as it were, lengthened the transformer windings, and the entire load current flowed through them, naturally, these are additional losses, especially for low-voltage windings. This was the price for the simplicity of implementation, however, this irrationality was excluded in the designs of programmable chips, where these wires were immediately excluded on the RP14 connector and only the necessary ones were output in the form of an output cable. But I think, and you will agree with me, that it is not worth giving up on the early possibilities of direct voltage switching during the transition to a new control level, i.e. it makes sense to leave the Unicum transformer in the form proposed earlier and not to embed in it a relay unit or toggle switches or a mechanical machine. I know that many of you would like to bring the "Unicum" transformer "to mind" in this way, i.e. something to build in his body. And I say: "You don't need to build anything, but it's better to build it on!". Look at Fig. 19, where the relay block "sits" on the transformer. As you can see, the relay unit and the transformer are isolated volumes (when the cases are made in steel, the magnetic stray field of the transformer does not affect the relay, and due to the presence of a gap between the cases as high as the handle for carrying the transformer (~ 40 mm), the heat generated by the power transformer, practically does not heat the relay unit).
Four long rails protect the relay fork blades from damage during storage. On the upper plane of the transformer, reciprocal guide bushings-nests are additionally made. Similarly, it is possible to make a mechanical machine, but only with an electric drive (because it is inconvenient to rotate the handle at a level of ~ 40 cm from the field), and place the control panel-balancer of the electric motor reverse on the table in the same way as the toggle switch panel and the control panel of the described relay unit. The low-voltage control panel is connected to the X2 socket of the RG1N-1-5 type installed on the upper plane of the relay block, the cable to which is the RSH2 chip of the H1-29 version or similar for 16 contacts. The control panel has a HL9 turn-on indication LED and a common switch for all 8 SA9 control lines, it can serve as an emergency reset key for the voltage dialed by the SA1-SA8 switches, as well as turning on the voltage dialed without switching the windings (preliminarily) (the toggle switch panel did not have such a function). The relay block has eight LEDs HL1-HL8 indicating voltage supply to the windings of each relay block (indirectly turning on and indicating the selected voltage). However, the conversion of voltage by LEDs is not very convenient, so the relay unit can be equipped with an AC voltmeter to indicate the actual (rather than calculated) voltage at the output of the unit. When using a pointer device (voltmeter PV1 in Fig. 19), automatic (using additional contact groups of the K1K8 relay) switching of measurement limits (additional resistors) and their corresponding indication by LEDs are possible. There may be, for example, two measurement limits of 30 and 300 V, while the 300 V limit can be turned off automatically when any relay K6, K7 or K8 and their combination is turned on, i.e. at a rated voltage of 32 V, and the limit is 30 V at rated voltages up to 31 V. For the practical implementation of automatic switching of measurement limits, it is sufficient to use an AC pointer voltmeter with a measurement limit of 30 V and a separate additional resistor to it to expand the measurement limit to 300 V, as well as the availability of additional contact groups for opening at relays K6, K7 and K8, which should be connected in series, and connect the entire garland of these 3 groups in parallel with the additional resistor of the voltmeter. In this case, you can leave only three red LEDs HL6, HL7 and HL8 in the block, which are assembled into one "peephole", it will indicate the increased output (32 V) voltage of the block and the automatic activation of the 300 V limit of the voltmeter. In the designs of relay blocks, it is possible to use various types of electromagnetic relays with an operating voltage in the range from 9 to 15 V and a winding current <150 mA, i.e. winding power up to 3 watts. For example, to work with a transformer with a power of up to 200 W, relays of the RES9 types (passport RS4.524.201) and RES22 (passport RF500.131) with parallel connection of contact groups are quite applicable. For transformers with a power of 400 W, good relays are REN34 (passport KhP4500030-01), selected by the response voltage, also with parallel switching of contacts. To work with transformers with a power of more than 400 W, relays of the REN33 type (passport RF4510022) and contactors of the TKE (TKE103DOD) series showed good reliability. The use of automotive 24 V relays of the 3747 series may be promising, but they are not very reliable and have poor quality insulation. When manufacturing a relay unit, it should be borne in mind that in no case (even if they are in steel casings) can electromagnetic relays be placed close to each other. The fact is that the windings of the switched on relays create a common magnetic field (and quite powerful). And it may turn out that after turning on all or some part of the relay, when the winding of one of them is de-energized, its contact group will not switch because the armature of this relay will be held by the total field of the switched on relays located nearby and too close to it. And if the relay block is placed too close to a powerful power transformer, the magnetic stray field of the transformer will also be superimposed on this total field, which can also cause another type of parasitic switching in the form of vibration of the magnetic system of any relay of the block (for example, with weakened return springs) . Therefore, the version of the relay block shown in Fig. 19 seems optimal to me (steel casing of the block and placement of the block above the transformer with a significant gap (40 mm)). The leakage magnetic field of the transformer is weakened to a greater extent, and the length of the connecting wires is as short as possible. For installation and a smooth set of voltages from a universal transformer by means of a relay switch, it is convenient to use an electronic control panel on reversible meters. The proposed product has a number of additional functions and amenities, the implementation of which by means of precision mechanics is extremely complex and practically unrealizable in amateur conditions. These new features include combinations of direct binary code dialing modes, similar to the operation of a toggle switch, and sequential enumeration of code positions both in step-by-step mode with manual control and in automatically accelerated mode, which is equivalent to the operation of a mechanical machine with a manual and electric drive, respectively, and also the ability to return from any dialed combination instantly to a preset switch or reset to zero by simply pressing a button. It is also not easy to perform in mechanics a rearranged stop-limiter for the maximum value of the code (voltage), which can act together with the known limiters for the maximum (255) and minimum (0). The outputs of the electronic control panel in the form of a flexible thin cable, reinforced with a RSh-2 plug, act similarly to the switches SA1-SA8 of the "Unicum 2" control panel and are capable of directly switching relay windings with currents up to 150 mA. The same cable supplies power to the +20 V circuit with a maximum current of about 150 mA from the relay unit, but it is possible to power the console from a separate source of 9-15 V (average value 12 V DC). The remote control is a structurally finished product and in the manufacture of the structure is much simpler than the same mechanical machine. The basis of the console design is the top panel made of plexiglass 3 mm thick and 150 x 80 mm in size (Fig. 20), to which two printed circuit boards of the electronic circuit (Fig. 2,5) with dimensions 21 x 125 are attached from below with four M 72 screws with spacers mm (in fig. 20, the screws are at the corners of the dotted outline, which shows the perimeter of the printed circuit boards under the panel). Figure 21 shows that the top printed circuit board 1 is a false panel, and the printed circuit board 2, made in a planar version (surface mounting on the top side of the board), is the bottom of the structure (insulating base without holes for elements)
Thus, without a case box, a practically closed structure is obtained, the height (thickness) of which can be only 20 mm, and it can be operated without a case for some time, usually until some kind of piece of iron gets on the electronic board and for example, some microcircuit will fail, so I recommend not to abuse this opportunity and take care of the case box, in which this structure can be easily fixed with four M 2,5 screws through the holes in the front and rear panel piles (Fig. 20). On the top panel (Fig. 20), in addition to the described mounting holes, there are rectangular cutouts for the leashes of 10 switches, 4 button pushers, and round holes for the lenses of 39 LEDs (one hole ?5 mm and 38?3 mm). The LED lenses should "peek out" above the panel surface by no more than 1,5 - 2 mm so that they cannot be pressed in with your fingers and the tracks of the board 1 are torn off. All inscriptions of the top panel are made on a sheet of thick paper with the dimensions and all the holes of the top panel, and this sheet is placed under a transparent panel (plexiglass). The top panel of the remote control - the panel of controls and indications (Fig. 20) contains the so-called. (in military terminology) "computer" for quickly converting binary code (Bin) to decimal (Dec) and hexadecimal (Hex) and vice versa. LEDs - hints, lit by an electronic circuit, reflect the state of the counters and the position of the dialed code relative to the pre-set switches (8 pieces on the left). Enabled bits (log. "1") of the binary code are reflected by a column of 8 yellow LEDs, each of which is installed next to the corresponding switch. The preset switches and their corresponding indicators are marked in all possible ways: on the left, just the numbers of the switches (as we considered them from the very beginning), then a column with powers of two (exponents are usually used to indicate the weight of digits in digital circuits and programs, they differ from positional numbers by the fact that it is always one less, i.e. the count starts from zero) and, finally, to the right of the LEDs, the familiar values of the weight of the bits of the binary code. The yellow LEDs do not always light up against the preset switches that are on. Figure 20 shows an example that can be obtained after pressing the "Set" button or turning on the power of the remote control in the "S" position of the "Begin" switch of the initial installation, or as a result of stopping the enumeration of the code with the "Up" and "Down" buttons , or on the adjustable stop after locking the "Up" button in the "L" position of the "LIMIT" switch. This state (equality of preset and dialed code value) reflects a large LED in the center of the panel with a yellow glow. In all other cases, this LED lights up either green (if the dialed code is less than the preset) or red (if the code dialed in the counters is higher than the preset). This LED is controlled by a special electronic circuit called a digital comparator (comparison circuit). The presence of such an indicator is very convenient when recalculating codes and, in addition, this is the only (out of 39) LED that will remain lit after pressing the reset button "Reset" (green if there are presets, and yellow if not), signal "On" . Actually, the function of the "calculator" is performed by 30 LEDs, placed and signed, as shown in Fig. 20 on the right. These LEDs are assembled in two columns of 15 pcs. in each. The LEDs of the left column are red, marked with numbers divisible by 16 (from 16 to 240), and reflect the state of the decoder of the highest four digits of the binary code, and the LEDs of the right column are marked with numbers from 1 to 15 (left) and digits of the hexadecimal (hexadecimal) code (right) from 1 to f and reflect the state of the decoder of the lower four digits of the binary code (sometimes called tetrads or nibbles, senior and junior, respectively). When converting to a hexadecimal (Hex) code, the digits of the right and left columns are equal and are written that way, and when converting to a decimal (Dec) code, the number highlighted by green and red LEDs should be summed up. It should be noted that zeros are not displayed, and that only one LED can be lit in the red and green columns (if the LED is not lit in any column, then there is zero), and also that the sum of the numbers of the red and green columns is always equal to the sum of the numbers in the yellow column. The convenience of the "calculator" lies precisely in the fact that the summation of a different number of numbers (up to 8 at 255) using the yellow "weight" LEDs is reduced to adding a maximum of two numbers in the green and red columns, which can be easily and quickly divided in the mind. According to the example of Fig.20 for the decimal number 167: it is clearly seen that 167 = 160 (red) + 7 (green), and in binary code it is 10100111 i.e. you need to sum up 5 numbers (yellow) 167 \u128d 32 + 4 + 2 + 1 + 167 and the easiest way is to get it in a hexadecimal code, where 7 \u30d AXNUMX and you don’t need to sum anything at all. And after all, the XNUMX values written on the red and green LEDs are also read directly (if the other column is off). The top panel and the electronic cable are served by the electronic circuit fig.3. The basis of the circuit is an 8-bit reversible binary counter, assembled on two 4-bit counters 533IE7 (DD1, DD2). The connection of microcircuits DD1 and DD2 is implemented by connecting the outputs of the transfer (pin 12) and loan (pin 13) with the inputs of summation (pin 5) and subtraction (pin 4). The counting inputs of the lower tetrad of a byte are connected through the elements AND DD8 to the control and limiting circuit of the account. The data inputs DD1 and DD2 are connected to the preset switches SA1-SA8 and the resistors forming a log. "1" R1R8 for the corresponding switches, which in the closed position form a log. "0" on the lines A0-A7. Loading data (bytes) into the counter is performed with a log "0" at the input of enabling parallel loading (pins 11 DD1 and DD2 are combined). For manual control of the download (installation) is the button SB1 "S" (Set - installation) on the top panel. Automatic loading into the counter of a byte previously dialed by switches SA1 - SA8 can occur when the console is turned on (power is supplied to the circuit), if the initial setting switch SA9 is in the upper position, otherwise, after power is applied, the counter will be set to zero, regardless of the current presets. The control button SB2 "R" (Reset - reset) is also made with a short circuit to a common wire for the initial installation. But the counter reset pulse must have a log level. "1". Therefore, the SB2 button must be connected to these inputs through an inverter. The inverter on the DD6.1 element, in addition to inverting the signal from the "R" button, performs a logical OR function for low levels at the inputs, which made it possible to perform a count limiter on it from below. For this, it turned out to be sufficient to connect the output of the counter (pin 23 DD1) to the input 12 of the element DD6.1. It is not possible to organize the upper limit of the count in the same simple way. Therefore, a DD9 chip was introduced, at the output of which we get a log signal. "0" in code position 255, which will close the AND element DD8.1 at the counting input of the counter summation. This is the upper count limiter. The floating limit mentioned above (by presetting) is implemented using an 8-bit comparator assembled on 533SP1 microcircuits (DD10 and DD11) with increasing bit depth. The mode of operation (type of output signals) depends on the inclusion of the inputs of the comparator of lower tetrads (inputs 2,3,4 DD11). In the inclusion shown in Fig. 3, these inputs are connected to the log. "1", so the outputs of the comparator will have the following levels: at the output "=" pin 6 of DD10, a high level will appear when words A and B are equal and low in all other cases , at the output A B output 7, if the codes are equal, there will be low levels.
If the current code at the output of the counter (B) is greater than the preset code (A), then output 7 (A B) will go to a high logic level, which is applied through R10 to the output key VT35 of the HL18 LED, and as a result, HL39.2 will glow green, since output 5 will remain at a low logic level. As already noted, when the words are equal (A = B), outputs 5 and 7 are set to log. "0" levels and both HL39 LED crystals are turned on (three-pin two-color LED ALS331). To obtain a yellow glow, the current through the crystals must be different - through green (HL39.2) 34 times more than through red ((HL39.1). Therefore, the resistances of resistors R45 and R6 are different. The sum of currents through the LED should not exceed 20 mA, so the current through the green LED is 15 mA, through the red - 5 mA. Let's return to the implementation of the floating stop by introducing a comparator into the counter control circuit. Logic. "1" signal from pin 6 DD10 at A = B is fed through the inverter DD6.2 to one of the inputs DD8.1 (the inverse signal L is fed to pin 5 DD8.1). When L = 0, the DD8.1 element is closed if the SA10 "L" switch is open (Limit - restriction). This stop is optional and can be set to any position of the code, which is convenient for a "shortened" voltage range. Switch SA10 can also enter the full range of voltage changes from 0 to 255 V. The second position of the "Limit" switch is designated M (Maximum) and is only a reminder that there is an upper limiter, represented by the M signal at input 4 of the DD8.1 element and acts similarly to the L signal, but never turns off. The M signal is generated at the output 8 of the DD9 8I-NOT chip, which is also a comparator, but with a fixed setting in position 255. Element DD8.2 is not fully used, inputs 9 and 10 are free and connected to the log. "1". These inputs can be used to organize two areas for changing codes: with SA10 enabled, from 0 to Limit and a new area from Limit to Maximum. This will require another switch that switches the output DD6.2 (signal L) from input 5 DD8.1 to inputs 9 and 10 DD8.2. There is a possibility (with the upper limit set) of setting the counter in the out-of-bounds areas of the code as a result of the action of impulse noise. If this happens, you need to be able to quickly return the voltage to the limited area. For emergency mode, there is a reset button, and for a simple overload, there should be a D (Down - down) button. These are extreme cases, but in general TTL microcircuits have good noise immunity. Much depends on the quality of the filtering of the supply voltages and power blocking. The proposed circuit has a double voltage stabilization, implemented on integrated stabilizers of the KR142 DA1 and DA2 series, which is inexpensive and reliable. Two latches are assembled on the DD5 chip, controlled by buttons SB3 "U" (Up - up) - elements DD5.1 and DD5.2 and SB4 "D" (Down - down) - elements DD5.3 and DD5.4. They are designed to generate manual control pulses to increase (U) to decrease (D). The formation consists in suppressing the bounce of the buttons and opening the AND elements from the DD8 chip. Actually shapers - circuits C2, R15, R16 and C5, R23, R24. The generator on the elements DD7.2, DD7.3 with a generation frequency of 6 ... 10 Hz is used to implement the TURBO mode. The operation of the mode consists in automatic sequential imitation of pressing a button or key when it is held for more than 1,5 s. In our case, this mode is useful if you need to sequentially overtake the code by a large number of positions in one direction or another. With a generator frequency of 10 Hz, all codes from 0 to 255 will be enumerated in 26 s. The permission signal log. "1" is fed to input 1 of the DD7.3 element through the DD6.2 buffer inverter from the time delay formation unit (1,5 s) made on the DD6.4 element, which, when the U or D buttons are pressed, releases the time-setting capacitor C3, which is charged through the resistor R19 and after 1,5 s unlocks the threshold element on the transistor VT17 and diodes VD1, VD2. A log signal "6.3" appears at the output of DD1, and the generator starts to work. Pressing the U and D buttons at the same time does not lead to catastrophic consequences - the code simply switches alternately in two adjacent positions. Four-bit decoders of a binary code into a unitary 16-position code use the K155ID3 type (DD3 and DD4). Each of them decodes his notebook: DD3 - the older one (output lines B4 ... B7 of the counter) and lights up the column of red LEDs HL1 ... HL15; DD4 - junior (output lines B0 ... B3 of the counter) and lights up a column of green LEDs HL16 ... HL30. LEDs are connected directly to the outputs of the microcircuits. And since only one LED can be lit at a time in a column of LEDs, only two current-limiting resistors are used (one per column of 15 LEDs R25 for red and R26 for green. A group of output transistor switches (8 pcs.) Serves not only yellow LEDs HL31 ... HL38, but also the output cable and in total can switch current up to 1,2 A. The outputs of the switches are connected to the output lines of the counters B0 ... B7, and with a log. "1" at the key input, two transistors entering the key open, in the collector circuits of which the HL31 ... HL38 LEDs are connected through current-limiting resistors R37 ... R44 to a voltage of +12 V to create a sufficient control current for more powerful transistors VT9 ...VT16. The open collectors of these transistors are the outputs of the panel for switching the relay windings of the power switch to a common wire. The top PCB assembly is shown in Figures 4 and 5 (part placement and PCB drawing). The upper printed circuit board is a false panel of the remote control, which means that all controls and indications are located on it.
Above is only a decorative cover with holes. The gap between them is determined by the height of the highest components on the board, they are SA1 ... SA10 switches of the PD9-2 type with a height of 6 mm, so these switches must first be installed on the board and four spacers of the same height must be selected for the M2,5 coupling screws, 1 at the corners of the board. Yellow LEDs HL39...HL3 with a diameter of 10 mm are placed in a column with a pitch of 1 mm, like switches SA8...SA5, and in the other two columns - with a pitch of 1,5 mm (red and green). LEDs are mounted like this. First, all of them should be inserted into the holes of the board (observing the polarity), then temporarily tighten the panel and the board with screws and "push out" the LED lenses so that they look out over the panel by 2 ... XNUMX mm and everything is the same, after which it follows solder the LEDs and cut off the excess. Further, the entire installation must be carried out so that the height of the parts above the board does not exceed 6 mm. Button designs are critical here. There are no problems with the SB1 and SB2 buttons, the standard low-profile ones are easily selected, and the SB3 and SB4 buttons are almost absent for switching. In this case, you need to try to remake the buttons. There is a variant of a reliable button for switching based on small-sized relays REK-23. To do this, a hole should be drilled in their body for pushers with a diameter of 2 mm for direct impact on the contact group. Pushers can be picked up from calculators. The second critical node is the voltage regulator +5 V DA1 (at the top of Fig. 4). The microcircuit should be installed on a copper plate 1 mm thick and the upper spacer bushings, which will also be elements of the heat sink, should be ground off by this value. Transistors VT9 ... VT16 in Fig. 4 are shown conditionally, they should be laid on the board. It is advisable to install resistors R1 ... R8 on the top board, this will allow you to check the top board without the bottom one. The lower printed circuit board in Fig. 6 is made in a planar version and is connected to the upper board by 27 wires. The image in Fig. 6 easily turns into a photomask, for this it is enough to make a copy in full size and blacken the inscriptions on the sites. A countertype is made from the template (negative, contact method on sheet film), which is then superimposed on the board blank with foil coated with photoresist. After developing and drying the photoresist, the board is etched in the usual way in a solution of ferric chloride.
Mounting on the bottom board can also be done low-profile. The highest on the board can be capacitors C3, C4 and C7. If they are of the K53 type, then the height of the spacer bushings between the boards will have to be increased to 9 ... 10 mm, but you can pick up small-sized imported capacitors. To increase the noise immunity, the digital microcircuits of the board should be blocked by power supply with ceramic capacitors of the same rating as C6. The digital microcircuits themselves should be used in the TTLSH series, they have less consumption. Author: Yu.P.Sarazh
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