Portable device for measuring radioactive particles

Portable device for measuring radioactive particles

It includes a limiting amplifier pulses across the lamp L (1B1P), the sound stage control sealer ‘device adapted to small thyratrons MTX-90 and serves to supply particle counters blocking oscillator on the lamp L2 (2PІP).

With up-winding of the transformer pulse voltage is applied to selenium rectifiers (three columns ABC 5-1a) after rectification smoothing filter

YA70S56 and later served on the resistance of the particle counter. Variable resistor included in the anode circuit of the lamp L2, allows you to change the value of the rectified voltage from 350 to 2200. With resistance through the capacitor surge voltage is input to the limiting amplifier and then to the input of the sound stage control or input to the binary scaler on thyratrons MTX-90.

Binary CONVERSION cell has two stable states: in one case, the first lamp locked MTX-90, and the other is open, and the second, on the contrary, opened the first lamp and the second closed. If igniting anode thyratrons submit both the starting signal, the potential of an open cathode thyratron increase. Increased capacity of the cathode thyratron is transferred to the anode and the thyratron locked cell into another stable state. In the next cell scaler signal is fed to the resistance in the circuit cathode lamp previous cell. Before the start of counting by pressing the «Reset» thyratrons are set to zero (bottom row). Count the number of pulses counted scaler for a certain period of time (1 min.), Is carried out by adding the numbers written on the top row of glowing lights. The total number of pulses registered scaler with 12 binary cells, is 4095, which is sufficient, for example, for the majority of the experiments conducted in the field with plants. To test the scaler to its input voltage pulse is supplied from the relaxation oscillator, collected on a neon lamp MH-5. To control the speed of sound accounts, as well as to determine whether the tracer radiation («is» or «no») the instrument has a separate stage in the thyratron MTX-90, working on the headphones. The control voltages (filament, anode, and on the scaler in the anode circuit of blocking oscillator) is carried out with the help of micro-ammeter M-494 — 50 mA at full scale.

CONSTRUCTION AND INSTALLATION

All components of the device are placed on an aluminum chassis dimensions of 275×195 mm. On the front side of the chassis located knob device: switch «Sound Control», start rediscounting device, the switch «Control — Operation», «Reset» button, the rheostat intensity, circuit breakers power switch voltmeter, variable resistance blocking oscillator and the anode circuits scaler device socket to turn the meter and headphones, voltmeter, 12 mm holes for observation and counting of registered scaler pulses of luminous thyratrons and slot for storing mechanical counter. Sealer is mounted on the chassis of the plexiglass 245 XX dimensions 45 mm. Tires are made of tinned copper wire diameter

Vaganov

1 -1.2 mm. On the bus «Less anode» soldered resistors and capacitors chain cathodes for the top row of thyratrons and drag the bottom row of the chain. On the bus «Plus anode» are soldered resistance in the circuits of the anodes and the bus circuit «Reset» — capacitors that are in chains cathode lamps bottom row. Installation scaler is more convenient to start with soldering capacitors n resistors being connected to the respective buses. Properly assembled device usually starts immediately. When adjusting should pay attention to the resistance, with which the voltage is applied to the anodes of all lamps agency. It can be taken of the order of 180-510 com depending on the resistances in the circuits of incendiary anodes.

Of counting cells operate at voltages of 105-140 V and for a more stable operation should be served on them in 115-120. The specified power mode is set with the variable resistance 10 com-

Blocking oscillator is mounted on the corner of duralumin chassis measuring 100 X 45 X 35 mm. He set the lamp transformer and selenium rectifiers. A transformer core is assembled from transformer steel plates W-12 package thickness of 23 mm. The primary coil has 3000 turns of PEL-1 0.05, the secondary windings 6000 PEL-1 0.8, which increases — 20 000-22 000 turns of PEL-1 0.05. Every 2000 turns laid paper insulation. Attention should be paid to the need for good insulation between the windings. After assembly and testing of its transformer boil in paraffin. When adjusting the blocking oscillator should implement proper phasing of the transformer windings.

Limiting amplifier pulses collected on duralumin chassis dimensions of 35X35X35 mm. it mounted lamp (1B1P) and resistance to the capacitors. Power immediately runs steadily and does not require additional networking. As a voltage selector switch for voltmeter used ranges on three positions. With two toggle switches for two. carry position switch «Sound Control», «Enable scaler», «Control — Operation».

Particle Counter is mounted in a lead cylinder with a wall thickness of 2-3 mm Hg screen performs the role of radiation. AT . It is sawed aperture, the size of which The rated depends on the type of meter. The counter is connected to the device by using the core wire in the insulation, ending with a fork.

The device consists of a blocking oscillator n selenium rectifier with a filter cell. Voltage pulse is removed from the load resistance of the counter and through a capacitor fed to the headphones. In this device, a low voltage is applied counter operating at a voltage of 350 to 400. Transformer blocking oscillator has the following data on the core plate thickness 15 mm package, the primary winding includes 2500 secondary — 5000 turns and raises — 18 000 turns of PEL-1 0.05; The device is on the trouser leg of the battery pack to the hearing aid «Sound» — anode battery GB-45 SA-N battery heater NA-SA. Weighing device with a power supply of 1.2 kg.Televizory «Soyuz» and «Banner», developed by the collective, the designers of the elbow of the Leningrad radio plants, differ significantly from the previously released models.

These TVs first applied tetrode picture tubes with a rectangular screen and electrostatic focusing. New picture tubes allow you to get a good focus on the entire field, and enhanced image contrast. CRT screens are made of smoked glass. The line scan operate a new type of lamp. Loudspeakers installed in TVs elliptical. Installation is made IA uniform chassis with new normalized components and .detaley.

TV «Soyuz» I «Banner» designed to receive five television programs with their sound and transmission VHF FM radio stations operating in the range of 64-73 MHz.

They differ among themselves only TV picture tube type and speaker system. The size of the image on the TV «Soyuz» 210X280 mm (CRT type 35LK2B) TV «Banner» — 255 X 340 mm (CRT type 43LK2B).

Sensitivity IA all channels at least 200 mV. The clarity of the image horizontally is about 500 lines. Power Bass audio signal passes a frequency band from 100 to 6000 Hz at rated power 1W.

Weighs TV «Soyuz» 21.5 kg, and the TV «Banner» — 25.5 kg.

Schematic diagram and block diagram of a high frequency shown in Fig. 1 and 2.

The TVs applied fifteen radio tubes and five semiconductor diodes.

The receiving part is made by using a superheterodyne circuit for receiving signals sound of the beat frequency (6.5 MHz), the converted signals carrying the image and sound. The first five stages are common to the image and sound.

Receiver input unbalanced and is designed to connect the 75-ohm cable. At the entrance is provided a voltage divider (1: 10), used when taking close to the television station. When the signal is too large, it is possible cross modulation in the grid circuit lamp RF amplifier.

The input circuit is made on the transformer circuit.

RF amplifier stage (A1), the mixer and the local oscillator «(A2) contains on double triode 6NZP and executed together with Channel as a separate unit — unit high frequency type TAP-3.

RF amplifier assembled on a «grounded cathode — grounded grid», so that the TV has a high sensitivity.

By the cathode circuit of the first transistor circuit is connected to the grid via a capacitor C . The voltage from the circuit is supplied to the lamp through a divider formed by the capacitance of the tube and condenser water load of the first transistor is a circuit Seth Sgk2 who bypassed a large input conductance of the second transistor — amplifier with a «grounded grid» and has a bandwidth covering all five received channels, allowing it to switch it in the transition from one channel to another IA. This circuit is tuned to the frequency of the fifth television channel than compensated by the gain reduction when receiving high frequency channels, caused by the shunting effect of the increase in input impedance lamps. Thus it is possible to obtain a uniform gain in all channels. *

To ensure stable operation of the first transistor is applied to neutralize in the grid circuit. Capacitors Cos, Sub district capacity to form a bridge, in a diagonal grid which included the coil circuit to another — the anode circuit, Co «i S6H»

Load of the second transistor amplifier is an RF bandpass circuit

Left triode lamp operates mixer conversion scheme single-column, and the right transistor — the local oscillator circuit for the three points with a capacitive feedback, which provides high frequency stability.

Voltage is applied to the grid of the local oscillator mixer by inductive coupling between the coils is applied a negative voltage from the potentiometer is a regulator of contrast. Such adjustment within a large gain changes without affecting substantially the shape of the frequency response. The frequency response in the control unit PP grid point IA first channel mixer is shown in Fig. 4a.

Anode load of the mixer is U-shaped series resonant circuit Ramp 12, Tale, which lowers the reaction plate circuit of the mixer circuit in the grid and reduce the penetration of the local oscillator on the grid of the tube amplifier. U-shaped loop is connected to the anode of the lamp mixer stub RC-19 whose capacitance is a capacitance of the circuit.

Two-stage IF amplifier (LZ and P4) is made pentodes 6ZHZP, loads which are single resonant circuits, intermediate frequency of the image signals is 34.25 MHz. Notch circuits inductively coupled to the amplifier circuits and customized IA frequency close to 27.75 MHz, whereby IA IF amplifier frequency response is formed flat plot. This system configuration increases notch sound signal in the channel of the image.

The frequency response of the IF amplifier is formed by three circuits, which -from the SS circuit tuned to a frequency of 32 MHz, and the contours — at 30 MHz and 33.75 ‘MHz respectively.

Video amplifier IA is made pentodes 6ZHZP ich6P9 (L5, LB) with, complex correction in the high frequencies. The frequency response of a video amplifier warms peak in the region, the higher the frequency bandwidth, thereby increasing image sharpness.

Power beat frequency of 6.5 MHz., Stands loop / gain stage amplifies the IF channel audio 6ZHZP the lamp (s), anodic load which is a bandpass circuit tuned as IA frequency 6.5 MHz.

Limiter on pentode 6ZHZP (A8) works at reduced anode and screen voltage limit is thus equal to about 1 in.

The single bass amp sound signals collected on pentode 6P9 (Ltd.), loaded dynamic loudspeaker UGD IA-9 (the TV «Union») or IA two dynamic speaker 1GD, 2GD 9 and 3 (in the TV «Banner»). Tone control is carried out resistance # 26, included in the higher frequency correction circuit IA output of the frequency detector. In the «narrow band» high frequencies (6000 Hz). fall down by 8 dB.

The use of special schemes sync allowed for a small number of lamps to achieve tight synchronization with the interference-interlaced steady expansion.

To separate the clock frame and line voltage frequency of the image signals used two selectors made two triode tubes Aw and A12 respectively.

Formation of the human clock is produced in the anode circuit of the lamp selector personnel integrating a chain of L33S36 having a time constant of 2000 ms. This circuit suppresses the short horizontal synchronizing pulses and short pulses chaotic interference.

Formed by integrating a chain of vertical sync pulse of a negative polarity is applied to the anode and lamp blocking oscillator frame (second transistor L] 0).

With the charging circuit blocking oscillator off the voltage for blanking frame scanning. This voltage is generated from the differentiating circuit With «Lz9 and fed to the control electrode of the picture tube.

The output stage of vertical deflection of the lamp 6PSCH (Li) with transformer output is loaded by vertical deflection coil CC.

Adjusting the size of the picture, the vertical is carried out resistance. # 37, and the linearity of vertically-resistance.

Left (scheme) triode lamps, in addition to the function selector human clock, performs the role of the second oscillator at acceptance VHF FM stations, and operates at a frequency of 23.5 MHz. The anode voltage is applied to the lamp resistance to # 54. Television reception second local oscillator circuit Closed n anode voltage is equal to 60 because of the voltage drop across the resistance of the lamp current 6P13S screen. When receiving VHF FM stations ua anode receives full voltage 120, as 6P13S lamp is not working. High frequency voltage across the capacitor C34 is supplied to the circuit control grid lamp L4 IF amplifier signal picture. The voltage of the second local oscillator signal together with the transformed FM station defines palpation — 6.5 MHz, which selection and amplification is done in the same manner as when receiving the audio signal, accompany a television program.

For good noise immunity rocked horizontal sync comprises a selector, assembled on the left (on the scheme) triode lamp 6n1p (Lі2) unlocks a special impulse. about

2 ms before the arrival of each clock pulse. Interference pulses can cause the beginning of reverse only when the disturbance enters the gap between the leading edge of the clock pulse and the front pulse edge of unlocking. Due to the low probability of such a contact selector ‘works quite effectively.

The rectifier circuit is assembled by doubling the agency moschnїh ‘semiconductor diodes such as DG-Ts27. The latter have a small internal resistance, which allows. rectifier with a high efficiency and to reduce the communication circuit between the power output stages of TV.

The use of new high-capacity electrolytic capacitors (150 uF) provides a rectified voltage of 300 to IA output smoothing filter at a low level ripple.

To protect the autotransformer and germanium! diodes against overload and short-circuit the plus high voltage is turned on and 1.

In the food chain IF signal amplification stages image and sound is turned on an additional filter chain from Iasi ^. The voltage of the output stage amplifier LF (Ltd.) is applied after the decoupling of the chain. It should be borne in mind that the auto-transformer power circuit TV chassis is powered network, so it is impossible to ground the chassis.

When you receive transmissions 4M radio stations of the lamp (L6, Lee, A z, A and $ CRT) in the heating circuits of a special switching group, which also includes the anode circuit of the resistance to quench the excess voltage of the second oscillator circuit n LiSCw6.

Television made IA unified chassis in three blocks: a high frequency (TAP-3), a receiver unit of the image signals and sound Mr. chassis rectifier and scan.

Placing items on the TV chassis shown in Fig. 5 N 6.

A2

All components of the TV are designed to be weight and ease of technological simplicity.

PTP unit is mounted on a removable bracket. Attaching CRT 35LK2B n 43LK2B unified. Centering raster by means of two magnetized wire rings worn on the neck of the tube.

Lamps are strengthened without the screen caps, attracting special springs.

TV box is made of wood, simulated a valuable breed. Dimensions of drawers TV «Soyuz» — 440 X 420 X 467 ** TV’s «Banner» — 500 X 460 X 480 mm.

The TV «Ziama» speakers located on the front and side panels of the box, and the TV «Soyuz» — on the front.

Front of the television picture tube frame occupied by Mr. decorative grille. Safety glass picture tube installed in the grooves of the two decorative rods, of which the top is easily removable, allowing, removing the protective glass, wipe the screen from dust. The main controls are derived IA front panel (in the TV «Banner» as .dvuh double handles). This volume control with power switch

Handle switch programs and adjust the oscillator output to the side panel. Auxiliary control knob, frequency control lines YAZA frame rate, frame size, and linearity Rij vertically on the rear panel. There’s also placed the antenna socket, and locking connector block with fuses.

Televisions are equipped with an internal antenna, which allows favorable reception conditions (with sufficient napryazheinostyah field and the absence of a reflected signal) to do without external antenna.

From the Editor. As demonstrated by test production samples TVs «Ziama» and the Union «, they work well, the image is stable and has good clarity and contrast, sounds good. In their scheme, the design and execution of these TVs are at the level of modern TVs at very economical power consumption, and superior to many of the best foreign TV companies.

Radio amateurs, designers wishing to learn the design data of coils, transformers and other components, can get them in the department of technical advice magazine.

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