Category «Basic Function Circuits»

Retriggerable One Shot with 556 IC

Retriggerable one shot/monostable multivibrator circuit is a flip-flop circuit which give active output when an input is present, and hold the state for a predetermined period before turns to inactive state. The difference between retriggerable and non-retriggerable  is that retriggerable circuit gives period extension when the input is retriggered before the output changes to inactive …

Variable Frequency And Duty Cycle Oscillator

A discrete oscillator circuit shown in the schematic diagram below is  a variable duty cycle and variable frequency oscillator, can be used to produce rectangular wave. This circuit has frequency range of 60 to 1,000 Hz. This circuit consist of one UJT (uni junction transistor) and two transistors that provide positive going output when emitter …

Discrete 0.5-300 ms Monostable Multivibrator

Monostable multivibrator circuit produce a fixed pulse-width when the input is triggered.  The input is fed to CR1, which should be an open collector source since the TR1 would short the input to ground during the active state  appear on this circuit’s output.  The output of this circuit is tapped from the collector of TR2. …

Long Period SCR Timer

This is a SCR timer circuit. Here, SCR is used to drive the final actuator, the buzzer.  The time constanst of this circuit is determined by  R1 and C1. The buzzer will sound when C1 charges up to a desired level, it will cause the Q1 to conduct and triggers SCR1.  The use of FET …