|
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 Radiation indicator in the radio. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Dosimeters A transistor receiver with a radiation detector introduced into it not only acquires a new important function, but the combination of these two devices has obvious benefits: the case, power source, low-frequency amplifier and acoustic emitter can be common in such a "combine". Schematic diagram of the radiation unit built into the transistor radio receiver is shown in fig. 70. It is based on the radiation indicator "Storozh-R". Since these devices differ only in the form of an alarm signal (LED flashes there and tonal bursts here), here we will focus on the possible design of such a "combine", the docking of its components.
All elements of the indicator, with the exception of the SA1 switch, are mounted on a double-sided printed circuit board, the "mounting" side of which is shown in fig. 71. The foil on the side of the parts is used only as a zero bus-"ground", in the places where the conductors pass, circles with a diameter of 1,5 ... 2 mm are etched in it, and the junctions of the "grounded" conductors with it are shown in black squares. The height of the parts installed on the board should not exceed 8...9 mm. The Geiger counter is mounted on the board from the side of the printed conductors with the help of wire clips put on the anode and cathode leads, which are then soldered into the holes intended for them. A fully assembled radiation unit (its dimensions are 19x23x109 mm, weight 22 g) can be installed in the radio receiver as shown in Fig. 72, a. A through cut 11x109 mm is made in the wall of the case to pass the Geiger counter. To avoid possible damage to it (the meter case is very thin), a deep (-9 mm) overlay is glued to this cutout, which has the shape of an oblong box with slots - windows. Such placement of the radiation unit is possible if there is free space 12x19x109 mm in the radio receiver. The placement option shown in Fig. 72, b, will require more space - 21x19x109 mm. True, the dimensions of the receiver in this case will hardly change: the protective grill covering the cutout in the case (9x92 mm) can have a thickness of only 1,5 ... 2 mm.
But if the radio receiver is small or “packed” in such a way that it is impossible to install the radiation unit in it *, then it can be placed in a separate case (Fig. 73, a) and, having connected to the receiver with a thin three-wire cable, be worn as shown in rice. 73b. The SA1 power switch, which is used to connect the radiation indicator to a working receiver, can be installed in any place convenient for this. Often, it is possible to use one or another switching element of the receiver itself as a switch - for example, a free or not too necessary position of the range switch. The switched on indicator will not affect the operation of the receiver in any way - only rare (with a normal radiation background of 15 ... 25 pulses / min) acoustic clicks will appear against the background of the received program. The radiation indicator is designed for installation in radio receivers with a 9-volt power supply. But it can also be converted to work in receivers powered by 6-volt batteries. To do this, you only need to change the winding data of the transformer T1: winding II should have 5, and winding III - 2 turns of wire PEVSHO-0,12.,.0,15. Winding I remains unchanged - all the same 420 turns of PEV-2-0,07. Among transistor receivers, especially older ones, there may be models in which not the minus of the power source, but the plus is connected to the zero bus-"ground". In such cases, you only need to reverse the power of the indicator: connect it "+" to "ground", and the common wire to the "-" of the radio. The value of the resistor R6 is chosen within (10 ... 20) R, where R is the resistance of the radio volume control. The overlay or grating that protects the Geiger counter from possible damage is made of the same material as the receiver case. If it is high-impact polystyrene (usually it is), then for their gluing, you can use shavings of the same polystyrene (of the same color) dissolved in solvent 647. This essentially welded joint is characterized by high strength. The same glue is attached to the receiver housing and polystyrene racks - supports for the printed circuit board. They must have threaded holes for an M2 screw. Suitable racks, even with metal liners poured into them, are often found in the cases of discarded electrical and radio devices for various purposes. The difficulties of combining these two devices are obviously connected with the fact that ordinary household transistor radios were not originally designed for such an application. Of course, all the elements of the radiation block could be placed on a printed circuit board common with the radio receiver, providing in its case the corresponding "window" for the Geiger counter. Let us draw the attention of future designers of such "combines" to the features of the ULF, the inconsistency of the requirements imposed on it here. On the one hand, when working with a ULF radio receiver, it should have sufficiently small non-linear distortions, and on the other hand, when working only with a radiation indicator, it should have an extremely small power consumption close to zero in a pause (the current consumed by the indicator itself is <0,2 mA) . The energy efficiency of the radiation monitoring regime is not an end in itself - in doubtful circumstances, the radiation situation is monitored continuously. In conclusion, we note that the radiation indicator described here will retain its main function - the function of a device that monitors the radiation situation, even without a unit that generates an alarm signal. Therefore, if necessary (the absence, for example, of the K176LP1 chip), this node can be excluded (the DD2 chip, VD4 and VD5 diodes, resistors R8 ... R13, capacitors C8 and C9 are excluded, and pin 10 of the DD1.1 element is connected directly to pin 6 of the element DD1.3). *) The radiation sensitivity of the Geiger counter depends on its size (see Appendix 4). In an effort to certainly fit into the dimensions of a small-sized receiver, we could also use a small-sized Geiger counter, the same SBM10 or SBM21. But a significant (by 6...10 times) decrease in radiation sensitivity would hardly be justified in a device of such purpose. Publication: cxem.net
A New Way to Control and Manipulate Optical Signals
05.05.2024 Primium Seneca keyboard
05.05.2024 The world's tallest astronomical observatory opened
04.05.2024
▪ Transformer on vegetable oil ▪ Working at night is hazardous to health ▪ Blind Spot Monitoring in Mercedes-Benz Trucks ▪ ASRock Z390 Phantom Gaming Motherboards
▪ site section Electric motors. Article selection ▪ article Old but golden. The art of audio ▪ article How old did one American live, actually remaining a one-year-old baby? Detailed answer ▪ article Scandinavian fjords. Nature miracle
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