SU1661972A1 - Flip-flop - Google Patents

Abstract

The invention relates to a pulse technique and can be used in contactless switching devices of large currents. The aim of the invention is to expand the scope due to the possibility of changing the trigger threshold. The device contains the first N - P - N transistor 1, the second P - N - P transistor 2, four resistors 3 - 6. To achieve this goal, Zener diode 8 and new functional connections are introduced into the device. 1 il.

Description

The invention relates to a pulse technique and can be used in some automation devices for contactless switching of currents (from 0.1A and more) of sufficiently powerful circuits,

The purpose of the invention is the expansion of the scope due to the possibility of changing the trigger levels of the trigger.

The drawing shows an electrical schematic diagram of a trigger.

The trigger contains the first 1 l-r-p-transistor, the second transistor 2 r-p-p-transistor 2, the first 3, the second 4, the third 5 and the fourth 6 resistors, a load resistor 7, a zener diode 8, the first 9 and the second 10 bus power supply and input 11. The base of the first pnp transistor 1 is connected to input 11, the collector through the load resistor 7 to the first power bus 9 and through the first resistor 3 to the base of the second pn-transistor 2, which the fourth resistor 6 is connected to the second power bus 10, which is connected through the second resistor 4 to the collector of the second r-p-transistor 2, emitt p is connected to the emitter of the first n-p-n transistor 1 via a third resistor 5 - 9 to the first power bus and to the cathode of the zener diode 8, the anode of which is connected to the second power supply bus 10.

The trigger works as follows.

The voltage from the collector of the first transistor 1 is supplied to the base of the second transistor 2 through the first resistor 3. The second 4 and fourth 6 resistors together with the first 3 resistor 3 determine the static mode of the second transistor 2. The circuit, consisting of a zener diode 8 and a third resistor 5, sets the initial level trigger operation, supporting a certain potential of emitters of the first 1 and second 2 transistors.

When the level of the input signal of the emitter potential of the first transistor 1 increases, the transistor starts to open, the voltage on its collector decreases, which causes a decrease in the base potential of the second transistor 2. Since the base potential of the second transistor 2 becomes lower than the emitter potential, the transistor opens, which leads to the full opening of the first transistor 1. The current in the load resistor 7 increases to) maximum, but when the input voltage decreases, the transistors close even at a lower level In comparison with the original, since the open trench transistors emitte5 potential is not determined by Zener diode, and the voltage drop at the open second transistor 2 and the second resistor 4, thus there is the hysteresis of the output characteristic of the trigger.

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Claims (1)

Claim A trigger containing a p-pn transistor, a second p-p-transistor, a first, second power bus, a first, a second, a third, a fourth resistor, the base of the first transistor connected to the input of the device, the collector through the first resistor with the base of the second transistor, the collector of which is connected to the first output 0 of the second resistor, characterized in that, in order to expand the scope by providing changes in trigger levels, the emitter of the first transistor is connected to the emitter of the second 5 transistor and through the third resistor with the first power bus, which is connected through the load resistor to the collector of the first transistor, the base of the second transistor is connected through the fourth resistor Ό to the second power bus connected to the second terminal of the second resistor and to the zener diode anode, the cathode of which is connected to the emitters of the first and second transistors,