|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING AAA photo battery. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Chargers, batteries, galvanic cells I propose to make a technically finished product from available materials, even from "amateur radio garbage" that accumulates in workshops. You can find failed powerful transistors that once worked, for example, in a home-made ULF, PSU, ... or were removed for replacement from industrial products. Among the scraps of foil material there is always a piece of double-sided fiberglass 1,5 mm thick and 40x8 mm in size. Among the fasteners, you can find two bronze chrome-plated contact screws: one M4x5 with a large head D8 mm and the second M2,5x5 with a well-formed head D3 mm. You will also need a washer made of thin getinax D8x2,5, 1 mm thick (preferably with a layer of foil on one side) and a piece of glass tube Dout = 10 mm (10,4 ± 0,2 mm) with a thick wall ? 1 mm 42 mm long and capacitor type K53-4 with a capacity of 4,7 uF x 6 V. It is assumed that you are a radio amateur, and you have the necessary set of tools (soldering iron, tweezers, etc.) and consumables (alcohol rosin flux, epoxy glue, acetone and chemical compositions for etching circuit boards, etc.). The resulting product is a technically finished photocell with a maximum output current of 1,5 mA and an output voltage of 1,5 V, and the voltage is stabilized and guaranteed at high levels of ambient light - sunlight from an incandescent lamp with a power of 60 ... 10 W from a distance of 150 mm. In the latter case, a capacitor is used to suppress the ripple of the output voltage with the mains frequency. The whole structure is placed in the dimensions of a galvanic cell of standard size "AAA" (10,4±0,2 mm l=44,4±0,2 mm) and is a glass capsule with contacts on the ends. In the proposed design, we use crystals of powerful bipolar low-frequency transistors of the KT802A, KT803A or KT808A types. These transistors are made according to the mesa-planar technology, which is characterized by the execution of the base and emitter electrodes in the form of mutually incoming combs from a metal deposited on the surface of a silicon crystal (Fig. 1, an n-region is created under the emitter electrode, and the base electrode is deposited directly on the silicon surface p-type).
The U-region of the collector is made on the other side of the crystal and is in contact (soldered) with the substrate, which, in turn, is soldered to the base area of the transistor housing. The crystals of the listed types of transistors have a nominal area (from the popular transistors of this technology) of 5x5 mm and are soldered onto an 8x8 mm substrate, which is easily removed from the transistor housing along with the crystal (unlike other types of transistors, for example, KT805, KT903, in which the crystal is soldered on the platform of the base of a massive body without a substrate and is removed much worse, besides, the crystals are much smaller). The crystal is coated with a transparent, heat-resistant protective varnish, through which the mesa-planar structure is clearly visible. We use the planar comb electrode of the base in the form of a "translucent electrode", it is better to carefully remove the emitter output wire. You can use transistors (crystals) with a damaged emitter junction. The criterion for the suitability of a crystal for the described application is the integrity of the collector pn junction and the photo-EMF value of 0,5 V (typical), which must be checked after opening the case of the device by illuminating the crystal with an incandescent lamp or in sunlight - by measuring the voltage between the terminals of the base and the collector (case ) a voltmeter with an input resistance of 10 kOhm/V. Transistors that have been overheated for a long time or electrically punctured may have a lower photo-emf. Having thus selected the transistors, we will remove the substrates with crystals. The easiest way to do this is in the kitchen near the gas stove. The case covers must be removed and the die leads separated from the case leads (cut cleanly without damaging the die) before doing this! We take the transistor by one of the terminals of the case and with pliers we hold the case over the burner with the terminals down in the left hand; in the right hand there should be tweezers, with which, after the solder is melted, the substrate with the crystal is removed. The substrate is tinned with a plastic special solder, so the solder (the same) should be removed from the bases of the transistors for subsequent use when landing the crystal on the board (Fig. 2).
The 8x40 mm printed circuit board contains 3 pads for soldering crystals (photocells V1, V2, V3, which used to be transistors) 8x9 mm in size. Crystals on 8x8 mm substrates should be planted on these sites so that it is possible to solder the base leads (anodes, pluses) of neighboring valves in series consonant inclusion. The pads and cutouts on the ends are designed for soldering contacts made of bronze chrome-plated screws, in which threads should be cut off to facilitate soldering. On the reverse side, the output pads are elongated and are pads for soldering the capacitor C1. To fit the structure into a circle of D8 mm (internal diameter of the housing tube), a sample is made under the capacitor, which reduces the height of its installation and the dimensions of the assembly. Solder the contact screw first; under the head of a small screw (M2,5, contact "+") put a dielectric washer (best of all, from a thin foil material with foil to the board in order to fix the washer by soldering on the end). And the sites for planting crystals on the board should be irradiated with solder, removed during their dismantling from the case, and coated with alcohol-rosin flux. The capacitor and contacts can be soldered with any solder, for example, POS-61, but it is better to solder the substrates with crystals with the same solder on which they were soldered to the base pad of the case of the former transistor, so the pads under the valves should be irradiated with the same solder from the transistor and covered alcohol-rosin flux. After irradiating the base lead and removing the emitter one, I recommend soldering the substrates with crystals as follows (Fig. 3): fix the board, take the crystals on the substrate in the left hand (in cotton gloves or through a napkin) and put them on the pad for 3... 4 mm, and with a soldering iron in the right hand we warm up the area (tinned and covered with flux, like the base of the substrate). The solder will melt rather quickly, and the substrate will be pulled up to the board by surface tension forces. After that, carefully move the soldering iron to the edge of the board, and the substrate onto the board. When the soldering iron comes off the board, the substrate will still be on the molten solder for a few seconds, and it can be accurately positioned and held until the solder solidifies.
After that, quickly solder the conclusions of the bases to the sites. Next, we check the voltage and photocurrent (1,5 V x 1,5 mA), wash it in acetone or alcohol, place the printed circuit board assembly in a glass tube (housing) and fix it with a few drops of epoxy glue in the area of \u2b\uXNUMXbthe contact screw "-" and around the perimeter of the washer contact "+" (fill the gap between the screw, washer and tube) (see Fig. XNUMX, a-c). Such photobatteries can be connected in parallel (to increase the photocurrent) or in series (to increase the voltage) in any quantity, as well as use combined options, making up a battery with the desired parameters. You can make them as blanks arrive and install them in standard power compartments of obsolete watches, for example. The use of cases made of transparent polymer is undesirable, due to the loss of optical transparency due to the low resistance of the surface to abrasion, so glass is better, although it is less impact resistant. If you have an optically transparent compound like epoxy resin at your disposal, then you can form an optical element - a lens, by filling a part of the body tube height with this material during assembly (in Fig. 2 (A-A) it is shown by a dotted line in the upper zone above the crystals). Due to the concentration of light by the lens, the sensitivity will increase. Although such a photocell already has a fairly good sensitivity, this allows it to be used as a light sensor. The described design is also good in that the normal of the crystals can be oriented to the light source by rotating the housing in a vertical plane around the longitudinal axis (in the elastic clamps of the cassette), and at the same time in the horizontal plane (parallel to the longitudinal axis passing through the axis along the normal to the crystals) a very wide viewing angle and does not require a tracking system for the light source (primarily the Sun). Author: Yu.P.Sarazh
Machine for thinning flowers in gardens
02.05.2024 Advanced Infrared Microscope
02.05.2024 Air trap for insects
01.05.2024
▪ Compact amateur 4K camcorder Sony Handycam FDR-AX100E ▪ Elpida XDR DRAM memory chips ▪ Intel sold 1.000.000.000 processors in 25 years ▪ Mechanism that turns smells into memories discovered
▪ site section Batteries, chargers. Article selection ▪ The bird of God knows neither care nor labor. Popular expression ▪ What were the results of World War II? Detailed answer ▪ article Bird cherry Maak. Legends, cultivation, methods of application ▪ article Car mirror defroster timer. Encyclopedia of radio electronics and electrical engineering ▪ article Odor Absorption by Porous Substances. Chemical experience
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page