SU892724A1 - Electronic switch - Google Patents

Description

(54) ELECTRONIC KEY

one

The invention relates to a pulse technique and can be applied to control a load varying over a wide range.

A device comprising a transistor, a source of control current and a load 1 is known.

A device containing two control current sources is known, the first terminals of which are connected to the common bus and the second connected to the base of the transistor and the cathode of the diode, the anode of which is connected to the emitter of the transistor and through the current sensor to the common bus, the collector of the transistor is connected to the power bus C2.

A disadvantage of the known devices is that they retain their parameters only with a small range of load variation. .

The purpose of the invention is to expand the allowable range of load variation.

The goal is achieved by the fact that an electronic switch containing two sources of control current, the first conclusions of which are connected. with a common bus, and the latter are connected to the base of the transistor and the cathode diol.

the anode of which is connected to the emitter of the transistor and through the current sensor with a common bus, the collector of the transistor is connected to the power supply through a load, a zener diode, four resistors and a voltage follower are introduced, the output of which is connected to the base of the transistor through the first resistor and

10 by the emitter of the transistor, through the third resistor with the bias bus and through the fourth connected in series, and the zener diode with the collector of the transistor.

15

 The drawing shows a diagram of the electronic key.

The electronic switch contains a transistor 1, a diode 2, a current sensor 3, a voltage follower 4, resistors 520 8, a zener diode 9, a load 10 and sources 11 and 12 of the control current, the first terminals of which are connected to the common busbar 1 and a diode 25 Da 2, the anode of which is connected to. see the transistor 1 and through the current sensor 3 c. The common bus, the co-collector of the transistor 1 through the load 10 is connected to the power supply bus 13, the output of the repeater 4 through the resistor 8 is connected to the base of the transistor 1, and the input through the resistor 5 is connected to the emitter of the transistor 1, through the resistor 6 to the offset bus 14 and serially connected resistor 7 and zener diode 9 With collector of the transistor 1.

The electronic key works as follows.

When source 12 is turned on (source 11; turned off), transistor 1 closes, Zener diode 9 punches and conducts a current, as a result of which the maximum positive voltage is established at the output of repeater 4. A current flows through the resistor 8, thereby reducing the current through diode 2, which makes it easier to unlock transistor 1. When source 12 is disconnected, source 11 is connected to transistor 1 base. A current equal to the sum of current from source 12 and current through resistor 8 is set to unlock it. The total base current must provide the unlocking of the transistor 1 at the maximum current in the load 10. After unlocking the transistor 1, the Zener diode 9 does not conduct, and under the influence of the signal from the bus 14 to the input of the repeater 4, a potential linearly dependent on its output the emitter of transistor 1 and, accordingly, from the current in the load 10. As a result, a current flows through the resistor 8, the magnitude and direction of which provide, together with the current of the source 11, the required degree of saturation of the transistor 1, which is usually minimal, which creates a condition for fast key locking. Thus, the shred allows to provide speed and reliable unlocking in a wide range of variation by. loads.

Claims (2)

1.Fremke A.V. Telemetry 0 m., Higher School, 1975, p. 175, fig.5.11 .. 2. Authors certificate of USSR I 493026, cl. H 03 K 17/60., 03/06/74.