SU920881A2 - Timer - Google Patents

Description

(54) TIME RELAY

one

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The invention relates to automation and is intended for use in blocks of the formation of commands with a certain delay.

According to the main author. St. No. 513496 knows a time relay containing field and bipolar transistors, a DC source, a time setting RC circuit, a voltage divider connected to a common and positive power supply busbars, and a midpoint with a source of a field-effect transistor. connected to the common point of the RC circuit, and the drain to the base of the bipolar transistor, the RC capacitor of the RC circuit is connected to the collector 1 of the bipolar transistor 1.

A disadvantage of the known time relay circuit is the complexity of the time relay self-hold circuit in the actuated state, the long duration of the time relay to its initial state for re-activation, as well as the possibility of false triggering of the time relay, with a residual potential on the plates of the RC depie.

The purpose of the invention is to increase speed and reliability.

This goal is achieved by the fact that in the time relay, the field and bipolar transistors are contained, the DC source, the time setting the RC circuit, the voltage divider connected to the common and positive power supply buses, and the midpoint to the source of the field-effect transistor, the gate which is connected to a common point of the RC circuit, and the drain to the base of the bipolar transistor, the capacitor of the RC circuit is connected to

10 a bipolar transistor collector, an additional capacitor is introduced, the negative pole of which is connected to the gate of the field-effect transistor, and the positive pole to the positive pole of the power source. The electrical circuit of the proposed time switch is shown in the drawing.

20 The device contains field I and bipolar 2 transistors, a time setting RC circuit consisting of a capacitor 3 and a resistor 4, a voltage divider on resistors 5 and 6, resistors 7 and 8, a capacitor 9.

The device works as follows: m.

When power is applied to the time relay, the voltages on resistors b and 4 are compared.

Depending on the charging time of capacitor 3, the voltage drop across resistor 4 will decrease before opening | field-effect transistor 1, which, opening, translates into saturation mode due to the fall of the voltage-and-on-resistor 7 bipolar transistor 2.

On the collector of an open bipolar transistor 2, the negative potential pushes the capacitor 3 of the RC circuit, and the auxiliary capacitor 9 remains charged, thereby eliminating the recharging of the capacitor of the RC circuit, therefore the time relay and in the de-energized state remains arbitrarily long .

When the positive pole of the power supply is disconnected, the time relay is immediately ready to be switched on again, as when the source is turned on again, the positive potential through the capacitor 9 goes to the gate of the field-effect transistor 1 and completely discharges the capacitor 3 of the RC circuit, thereby eliminating the possibility of a false load time relay and its transfer to the initial state.

Claims (1)

Invention Formula Timer on aut. St. No. 513496, distinguished by the fact that, in order to increase speed and reliability, an additional capacitor is introduced into it, the negative pole of which is connected to the gate of the field-effect transistor, and the positive one to the positive pole of the power supply. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 513496, cl. H 03 K 17/28, 1974. +