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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Christmas tree garland switches. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Color and music installations, garlands On the eve of the New Year, many radio amateurs are concerned about the question: how to revive the New Year tree? Below are several options for Christmas tree garland switches, differing in the degree of complexity and lighting effects implemented. The simplest switch alternately switches two garlands (Fig. 38). A generator is made on the logic elements DD1.1, DD1.2, and high-voltage switches are assembled on transistors VT1, VT2 to control the trinistors VS1, VS2. Power is supplied to the microcircuit from the parametric stabilizer R4VD1 with capacitor C1. The constant voltage for both the DD1 chip and the EL1, EL2 garland lamps is taken from the VD2 rectifier bridge.
To create the "Running Fire" effect, you must alternately switch at least three garlands. The diagram of the switch (the first option), which controls three garlands, is shown in fig. 39. The basis of the device is a three-phase multivibrator, made on three inverting logic elements of the DD1 microcircuit. Timing circuits are formed by elements R1-R3, C1-C3. At any moment, there is a high-level voltage at one of the outputs of the logic elements, which opens the transistor-trinistor switch. Consequently, the lamps of only one garland are lit at a time. Alternately switching the lamps of garlands EL1-EL3 allows you to get the effect of "Running fire".
The inverters of the K555 and K155 series microcircuits can work in the multivibrator. In the second case, the resistance of resistors R1-R3 should not exceed 1 kOhm. You can also use CMOS microcircuits (K176, K561), while the resistance of the timing resistors can be increased by 100 ... 1000 times, and the capacitances of capacitors C1-C3 can be reduced by the same amount. Changing the switching frequency of garlands can be done by changing the resistance of resistors R1-R3. It is difficult to control them at the same time (industry does not produce built-in variable resistors for widespread use). This is a disadvantage of this garland switch. On fig. 40 shows a diagram of a garland switch (second option) with an adjustable speed of the "Running Fire".
How does this device work? On the logic elements DD1.1, DD1.2, a generator of rectangular pulses is assembled, the repetition rate of which is 0,2 ... 1 Hz. The pulses are fed to the input of the counter, which consists of two D-flip-flops DD2.1 and DD2.2 chip DD2. Due to the presence of feedback between the element DD1.3 and the input R of the trigger DD2.1, the counter has a conversion factor of 3 and at any time one of the transistors VT2-VT4 is closed. If, say, VT2 is closed, then a positive voltage from its collector will be applied to the control electrode of the trinistor VS1, the trinistor will open and the lamps of the EL1 garland will light up. The switching frequency is regulated by a variable resistor R3 of the generator. In the device, the K155 series microcircuits can be replaced with the corresponding analogs from the K 133 series. Transistors VT1-VT4 can be from the KT315, KT3117, KT603, KT608 series with any letters. Trinistors VS1-VS3 can be types KU201, KU202 with the letters K-N. The source that feeds the microcircuits and transistors of the device must be designed for a current of at least 200 mA. The disadvantage of the switch is the need to use a transformer power supply. This is due to the relatively large current consumed by the K155LAZ and K155TM2 microcircuits. It is possible to significantly reduce the current consumption by using CMOS microcircuits, in this case the microcircuits can be powered from a simple parametric stabilizer, as is done in a two-garland switch (see Fig. 38). The diagram of the switch of three garlands (third option) on the K561 series microcircuits is shown in fig. 41, a. The generator is made on the logic elements DD1.1, DD1.2, and the counter with a conversion factor of 3 - on two D-flip-flops of the DD2 chip. Plots of voltages at the outputs of logic elements are shown in fig. 41,6. They will help to understand the logic of the device. Transistor-trinistor keys for controlling garlands, a rectifier and a stabilizer for powering microcircuits are the same as in the switch according to the diagram in Fig. 39 (in this case, you need to use KS1Zh or D191V as a zener diode VD814).
The "Running Fire" devices described above have a common drawback: the immutability of the logic of work. Lamps in garlands switch only in the prescribed order, you can only change the switching frequency. At the same time, it is desirable that the illumination be as diverse as possible, and not bother or tire the eyesight. This means that it should be possible to change not only the duration of the lamps, but also the sequence of their switching. On fig. 42 shows a diagram of a garland switch that meets these conditions.
The "heart" of the device is the K155RU2 chip - a random access memory for 16 four-bit words (in this case, a word means a set of logical zeros and ones, for example, 0110, 1101, etc.). How does such a microchip work? Its four inputs (D1-D4) are designed to supply information that needs to be written to memory. These inputs are called informational. Four other inputs (A1-A4) are supplied with a binary code of the address of the cell that you want to select for writing or reading information. These inputs are called address inputs. By changing the binary code on these inputs from 0000 to 1111, you can access any of the 16 cells. By applying a signal to input W, the desired operating mode of the microcircuit is selected: if the voltage at the input W is low, then the cell is written to, and if the voltage is high, then information stored in the memory cells of the microcircuit can be read. When reading information is fed to the outputs C1-C4. The outputs of the microcircuit are open-collector, and if a logical 1 is written in the memory cell, then the corresponding output transistor will be open (of course, a load - a resistor must be included in its collector circuit). Thus, to write a number to any memory cell, it is necessary to apply the appropriate logic levels to the inputs D1-D4, and the binary code of the address of the required cell to the inputs A1-A4. Then a low-level voltage is applied to the input W - and the information is recorded. To read the information, it is necessary to apply a high-level voltage to the input W. Then, when the address code is changed, signals corresponding to the contents of the corresponding cells will appear at the outputs C1-C4. The V input is used to enable the operation of the microcircuit: when a high-level voltage is applied to it, writing and reading are not performed. Consider the operation of the switch according to its circuit diagram. Using the buttons SB6 "Start" and SB7 "Reset" set the required mode of operation of the device: after pressing the "Reset" button, you can write the program to the memory cells of the microcircuit, and after pressing the "Start" button, the recorded program is read. When you press the button SB7 "Reset" RS-flip-flops collected on logic elements DD1.1 and DD1.2, DD1.3 and DD1.4,DD2.1 and DD2.2, DD2.3 and DD2.4, DD4.1. 4.2 and DD1.1 will be set to the initial state, in which the outputs of the logic elements DD1.3, DD2.1, DD2.3, DD4.1 and DD12 - low voltage. Arriving at pin 4.4 of the logic element DD4.3, it disables the operation of the clock generator assembled on the logic elements DD4.4, DD1 and the transistor VTXNUMX. Then, using the buttons SB1-SB4, a binary word is typed to be written to the first memory cell. Let's say we need to write 0111. To do this, press the buttons SB2, SB3, SB4. In this case, the triggers DD1.3DD1.4, DD2.1DD2.2, DD2.3DD2.4 will switch and the LEDs HL2, HL3, HL4 will light up. After that, press the button SB5 "Record". The pulse from the trigger output (pin 3 of the logic element DD3.1) through the differentiating circuit C2R13 and the logic element DD3.3 is fed to the input W of the memory chip DD6. The differentiating circuit C2R13 and the logical element DD3.3 work in such a way that after pressing the SB5 "Write" button, a short (several nanoseconds long) negative pulse arrives at the input W, which ensures the recording of the information supplied to the information inputs D1-D4 at the address in accordance with binary code on address inputs A1-A4. At the moment the SB5 "Record" button is released, the pulse from the output of the logic element DD3.1 through the capacitor C1 will reset all RS-flip-flops into which the binary word was previously written. The pulse received from the output of the logic element DD3.4 to the input C1 of the binary counter DD5 will increase the address by one (the binary code of which is taken from pins 12, 9, 8 and 11 of the microcircuit in question). Note that the address DD5 counter is not reset (pins 2 and 3 are connected to a common wire to ensure the counting mode). After that, using the SB1-SB4 buttons, a new binary word of the program is typed, the SB5 "Record" button is pressed, etc. - until the entire program of 16 four-bit binary words is written to the memory chip. After the program is written, press the button SB6 "Start", the trigger DD4.1 DD4.2 changes its state to the opposite, the generator starts to work on the logic elements DD4.3, DD4.4, the pulses of which are fed to the counter DD5 and change the address code cells. At the input W now all the time there is a logical 1, because the output of the logic element DD4.2 is logical 0, which is fed to the input of the logic element DD3.3. At the outputs C1-C4 of the K155RU2 chip, logic levels appear corresponding to the information recorded in the memory cells. The signals from the outputs C1-C4 are amplified by transistor switches VT2-VT5 and then fed to the control electrodes of the trinistors VS1-VS4. Trinistors control four garlands of lamps, conventionally indicated on the diagram EL1-EL4. Let's assume that there is a logical 1 at the output C6 of the DD0 microcircuit. In this case, the transistor VT2 is closed, current flows through the resistor R21 and the control electrode of the trinistor VS1, the trinistor opens and lights the lamps of the garland EL1. If the output C1 is logic 1, then the EL1 lamps will not light. The microcircuits of the device are powered by a stabilized rectifier assembled on a VD2-VD5 diode bridge, a VD1 zener diode and a VT6 transistor. The EL1-EL4 garland lamps are powered by a rectified voltage taken from the VD6-VD9 diode bridge. Switch Q2 is used to turn off the garlands, switch Q1 is used to disconnect other elements of the device from the network. The following parts are used in the device. Transistors VT2-VT5 can be any of the KT3117, KT503, KT603, KT608, KT630, KT801 series; VT1 - any of the KT503, KT312, KT315, KT316 series; VT6 - any of the KT801, KT807, KT815 series. Trinistors KU201L (VS1-VS4) can be replaced with KU202 with the letters K-N. Diodes VD2-VD5, in addition to those indicated, can be types D310, KD509A, KD510A; you can also use bridge rectifiers KTs402, KTs405, KTs407 (with any letter indices). Diodes KD202K (VD6-VD9) can be replaced with KD202 with the letters L-R, as well as with D232, D233, D246, D247 with any letters. Capacitors C1, C2 - type K10-7, K10-23, KLS or KM-6; C3-C5 -K50-6, K50-16 or K50-20. All fixed resistors are of the MLT type; variable resistor R 16 - SP-1, SP-0,4. The device can use buttons such as KM 1-1 or KM D 1-1. You can also use other types of buttons (for example, P2K without fixing the position). Switches Q1 and Q2 - type "tumbler" (TV2-1, TP1-2, Tl, MT1, etc.). The power transformer 01 is made on a tape magnetic circuit SHL 16x20. Winding I contains 2440 turns of wire PEV-1 0,08, winding II - 90 turns of wire PEV-1 0,51. You can use any other transformers with a power of 10 ... 20 W, having a secondary winding for a voltage of 8 ... 10 V and a current of 0,5 ... 0,7 A. Suitable transformers TVK-70L2, TVK-110LM, in which part of the turns of the secondary winding must be removed to obtain the desired voltage. Most of the elements of the device are mounted on a textolite board with dimensions of 120 x 145 mm (Fig. 43, a).
Installation is done with wires. The VT6 transistor is mounted on a duralumin corner with an area of about 30 cm ^ 2 (it serves as a radiator). Diodes VD6-VD9 and trinistors VS1-VS4 are installed on the board without radiators, while the total power of switched lamps should not exceed 500 watts. The SB1-SB7 buttons (KM1-1 type) are installed: on a PCB strap (Fig. 43,6), which is attached to the main board with two M3 screws. Outside the board are the following elements: power transformer T1, fuse holder FU1, power switches Q1 and Q2, variable resistor R16. The elements of the board are connected to them by a stranded wire. The wires connecting the anodes of the VS1-VS4 SCRs with the EL1-EL4 lamps are soldered directly to the SCR petals. The cross section of the wires with which the power circuits are made must be at least 1 mm2. The design of the device is arbitrary. On the top cover of the case there should be buttons SB1-SB7, power switches Q1 and Q2, program recording control LEDs HL1-HL4, as well as a variable resistor knob R16, with which you can change the speed of switching garlands. A fuse holder FU1 and sockets for connecting garlands are installed on the side wall of the case (they are not shown in the diagram). If all the parts are in good order and there are no errors in the installation, then the device starts working immediately. It should be noted that the achieved lighting effects largely depend on the relative position of the garland lamps. The most common is their arrangement, when the lamp of the first garland is followed by the lamp of the second garland, then the third, fourth, etc. In fig. 44 shows a diagram of such an inclusion of lamps. Switch programming is carried out as follows. First, a program is compiled on paper, which is a record of the state of the lamps of all four garlands in each of the 16 cycles of the device. The on state of the garland is indicated by logical 1, the off state is indicated by logical 0. Then, by pressing the SB7 "Reset" button, the device chips are set to their original state. After that, by successively pressing the SB1-SB4 buttons, the first word of the program is typed, paying attention to the ignition of the HL1-HL4 LEDs, and the "Record" button SB5 is pressed. This is how information is recorded in all 16 cells of the microcircuit. Then press the button SB6 "Start" - the switch goes into operating mode.
When programming, it should be remembered that information must be written to all 16 memory cells of the microcircuit, since when the power is turned on, the state of these cells is indeterminate. In table. 3 shows some options for programming the garland switch to obtain a variety of lighting effects. The logical 1s in each word from left to right indicate which of the buttons SB1-SB4 respectively should be pressed.
The first and second programs provide the effect of "running fire", the rest of the programs are more complex effects. The number of programs that can be implemented using this device is large, and this opens up scope for the operator's imagination. It should also be remembered that changing the speed of switching garlands opens up wide opportunities for obtaining various lighting effects. The total power of the lamps switched by the device can be increased up to 1500 W, while the VD6-VD9 diodes must be installed on radiators with an area of 40 ... 50 cm2 each. If a radio amateur has symmetric thyristors (triacs) of the KU208G series at his disposal, they can also be used to control garland lamps. Triacs should be connected in accordance with the diagram shown in fig. 45 (a diagram of only one channel is shown, the rest are similar). The resistance of resistors R21-R24 (see Fig. 42) in this case must be increased to 1 ... 3 kOhm. KT605A transistors can be replaced with KT605B, KT940A, VD6 diode bridges can be KTs402, KTs405 with the letters A, B, Zh, I.
The second version of the triac switching node is shown in Fig. 46.
Its difference from the previous one is that the transistor switches VT2-VT5 with resistors R21-R24 (see Fig. 42) are replaced by inverting logic elements of the DD7 microcircuit (resistors R17-R20 in the circuit Fig. 42 are preserved). Such a circuit design somewhat simplifies the design. The triac control unit can be made even simpler by using electromagnetic relays (Fig. 47). The relay windings, as can be seen from the diagram, are included instead of resistors R21-R24. The switch can operate any relay that operates from a voltage of 8 ... 12 V at a current of up to 100 mA, for example, RES-10 (passports RS4.524.303, RS4.524.312), RES-15 (passports RS4.591.003, RS4.591.004, RS4.591.006), RES-47 (passport RF4.500.049, RF4.500.419), RES-49 (passport RS4.569.424). In addition to a simple circuit design, there is another advantage - the galvanic isolation of the low-voltage part of the device from the power supply, which increases the safety of using the switch. The disadvantage is a shorter service life caused by wear of the relay contacts.
And finally, one more recommendation. When the power supply voltage is turned off (even for a short time - a few seconds), the program recorded in the memory chip is destroyed. Therefore, it is advisable to provide for emergency switching of the power supply circuits of the device microcircuits to power supply from a galvanic battery or accumulator. A scheme to implement this is shown in Fig. 48.
In normal mode, the switch microcircuits are powered by a rectifier, and the current flows through the VD11 diode. At the same time, the VD10 diode is closed, since a small (0,5 ... 1 V) reverse voltage is applied to it. When the mains power is turned off, the VD11 diode closes, but the VD10 diode opens, and the microcircuit is powered from the GB1 battery. Capacitor C6 dampens voltage pulses that occur when switching power from mains to battery and vice versa, and thus increases the noise immunity of the device. Diodes VD10, VD11 can be of any type, allowing a current of at least 300 mA (for example, D226, KD105 with any letters are suitable). Battery GB1 - 3336L. When using this node in the switch, you should pay attention to the output voltage of the rectifier: it must be 5 ... 5,5 V (but not less than 5 V), otherwise the GB1 battery may be constantly discharged. The duration of battery power depends on its capacity. With long power failures in the network (more than 15 ... 20 minutes), such an emergency power supply is impractical, since the garland lamps still do not work, and a new program can be dialed in just 3 ... 5 minutes.
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