SU1195424A2 - One-shot multivibrator - Google Patents

Abstract

ONE VIBRATOR on auth. No. 902223, characterized in that, in order to increase the noise immunity at the start by the electromechanical switch), a third capacitor is inserted in it, connected between the inputs of the logical element 2I-HE.

Description

t /.

nun.

Vmz

L | №yu

coke

4 GO

1 The invention relates to a pulse technique and can be used in electronic equipment as shapers for delay and pulse duration. The purpose of the invention is to increase the interference resistance when starting electromechanical shutdowns and those without lamination of the single vibrator. The schematic diagram shows the electrical circuit of the one-shot. The one-vibration comprises a logic element 2I-HE 1, an inverter 2, resistors 3 and 4, capacitors 5-7, a diode 8 and an electromechanical switch 9. Resistor 3 is connected between the trigger input of the logic element 2I-H 1 and the power supply bus. Electro mechanical switch 9 is connected to the triggering input of logic element 2И-NOT 1. Through code capacitor 6, logic element 2И-НЕ 1 is connected to the input of inverter 2, which is connected via a series-connected circuit - resistor 4 and diode 8 to the common source bus nutrition The connection point of the resistor 4 and the anode of the diode 8 through a capacitor is connected to the output of the inverter 2 and to the second input of the logic element 2INE 1. The capacitor 5 is connected between the inputs of the logic element 1. The single-oscillator operates as follows. . In the initial state, at the output of logical element 1, the level is O (C5), and at the input of the inverter, 2 is the logical level 1 (U.). Capacitors 5 and 6 are discharged, and capacitor 7 is charged before the voltage (U2 - Ug.), Where Cl is the voltage drop across the diode. When the contacts of the electromechanical switch 9 are closed between the triggering input 242 of the logic element 2И-НЕ 1 and the common power supply bus, the capacitor 5 starts charging along the circuit: the power supply bus is positive - the output resistance of the inverter 2 is the capacitor 5 - the electrical contact switch 9 is closed. The constant charge time of the capacitor 5 is defined by the expression CC-R where Rg, is the output impedance of the inverter 2; Cj is the capacitor capacitance 5. The capacitor discharge 5 occurs along the circuit: positive capacitor plate 5 - inverter output resistance 2 - power supply positive busbar resistor 3 - negative capacitor plate 5. Time constant of capacitor discharge 5 is determined where Tp is the resistance of the resistor 3. Thus, when the third capacitor is switched on in the known one-shot circuit between the inputs of the logic element 2I-NOT, the discharge time of the capacitor is constant when the devices start up electromechanical switch exceeds the constant charge time of said capacitor to a value equal to Cy-R-. Since the resistance of the resistor 3 considerably exceeds the resistance of the inverter 2 (when the one-shot is started, its speed is not lost, and when the contacts of the electromechanical switch are opened, the voltage is delayed at the trigger input of logic element 1 and thus the effect of bounce is eliminated.

Claims (1)

SINGLE-VIBRATOR No. 902223, characterized in that, in order to increase the noise immunity at start-up by an electromechanical switch, a third capacitor is inserted into it, connected between the inputs of the logic element 2I-NOT.