SU374734A1 - TWO-THRESHOLD DEVICE ^, • .- .., - .. -, -ioii ''! I;:;,> & it '' - ^ ... ' - Google Patents

Description

one

The invention relates to automation and can be used in automation devices, pulsed technique and instrumentation.

The well-known two-threshold devices, containing a current-stabilizing device and two current switches, in which the collector of the input T; paH3, KCTQpa of the first current switch is connected to the second transistor of the second current switch, have a low speed, m speed.

The purpose of the invention is to increase the speed of the device.

For this, the collector of the input transistor of the first switch is connected to a current-stabilizing device and an input of an additional amplifier stage on the base connected to the common base circuit.

FIG. 1 and 2 shows variants of electric circuits of two threshold devices; in fig. 3 —Time diagram of the device operation, where, induction is used as a current-stabilizing unit.

A double-threshold mouthpiece consists of two current switches, one of which contains trans-sources / and 2, and the other - T | rasistors 3 vi 4.

The bases of transistors / and 5 are connected to the input of the circuit, and the bases of transistors 2 - 4 - to

2

sources of reference stresses. The common point of the combined emitters of each current switch is connected to a separate current generator, made respectively on the transistor a 5 l 6. The collectors of transistors 2 and 5 are connected to a power source. The collectors of transistors 1 and 4 are connected to the output of a separate generator by a current-stabilizing element h made

on the transistor 7, the direction of the current of which coincides with the direction of the collector current of the transistor / and 4. In addition, the collectors of transistors 4 are connected to the emitter of the additional transistor 5, (connected to the common base. The collector of transistor 8 is the device outputs, and The base is connected to the power supply source.The circuit operation is explained by the time span of my Fig. 3. The response threshold of the first current switch is determined by the reference voltage i / 2- In each of the two current switches that transistor is open the base potential of which is lower, and the adjacent T1ra1nzistor in this switch is closed.

If the voltage at the input 9 of the device is higher than both of the reference 1a; pr: Zheniy, then transistor 2 is open in the first current switch, in the second - transistor 4. At the output of the circuit

through the transistor 8 flows the current of the 1st out r2-is.

The current generators on the THR. 5, 5 and 7 tuners are configured in such a way; M so that, as well, / 3 is less than "each of the two previous TQKOBs, to an unimportant 1". Thus, “and the output of the circuit 10 flows a discontinuous current determined by this difference. In the process of lowering the input voltage and at the time tl, it is compared with the reference voltage t / i of the first switch, that is. At this moment, the switch on the traistor 1 iH is set to T (rashistor 2. After that, both at the device output + time ta, the input voltage is equal to opistor B, which will cause IK to turn on the traistor 3 to turn off the transistor 4. at the output of JBbix i | -fj. Since so / s there are less currents tl and 12 "and a very small value not commensurate with these currents, this difference can be neglected. Therefore, we can assume that the output current at time between t and 4 JBbix ti t2, and the rest of the time f OUT 0.

TaKHiM, an IMPulse of current, the value of which is determined by such generators, appears on the output of the circuit at 11ranz 5 and 5, 7 1I 2, and the duration is in time of the input voltage drop; within the limits of the reference levels f / i and Uz- The smaller the difference between the currents gz and L (or yr), the more precisely the last two equalities are fulfilled, the closer (to zero) the current of the output in the absence of a pulse. This current can be made arbitrarily small. The need to have at least a small amount of current at the output of the circuit in the absence of an output pulse lies in the fact that the EMT – base transition of transistor 8 must be kept biased in the forward direction. This gives the advantage that when forming a current pulse at the emitter of a trap. Sistor 8 exhibits a very un-initial voltage drop, TaiK as a dynamic sap of an open junction. A small voltage drop is ob.S1pechi; vaet fast pbresar d parasitic capacitances, which provides high speed circuit.

In this way, at the output, the device gives an impulse tO (at a certain value,

the duration of which is determined by the duration of the front of the input signal, i.e., the time of the difference in the input signal, IB, between the reference levels.

Another schematic version of the task.

A two-pair device is shown in FIG. 2, where the role of such a stabilizing element is performed by an inductance coil //. Resistor 12 serves for the initial direct smegDeni | On the transition e, the miter-base of the transistor S, which provides high speed. The circuit (see Fig. 2) can be used with a high duty cycle of the output pulses, which is necessary to restore the current in the coil.

between output pulses.

Subject invention

A two-threshold device containing a current-billing device and two non-current switches in which the collector of the input transistor of the first current switch is connected to the collector of the onoipHoro transistor of the second switch of the current transistor, characterized by the fact that, for the purpose of fast output, the collector of the input transistor The first switch is connected to a current stabilizing device and an input to an additional amplifier stage on a transistor connected in accordance with a common base circuit.

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