AC triggered switch


Posted on Sep 16, 2012

An AC triggered switch for low frequency signals. This is a basic ac voltage operated switch made from discrete components. Both Q1 and Q2 work as common emitter amplifiers, but the biasing of Q1 is arranged by R3 and R4 so that about 0.5V is applied to its base; so with no input signal both transistors and the load is off.


AC triggered switch
Click here to download the full size of the above Circuit.

With an input signal greater than 0.3V pk-pk (100mV RMS) the positive half of the waveform will switch on Q1, and Q2 and the relay. As the input signal switches to its negative transition, Q1 will switch off, but base current in Q2 continues to flow via C




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

18-bit ADC uses PC`s serial port
Simulated inductor
Lighted-display-brightness-control
Xor-gate-oscillator
VFC110: Single Chip High-Frequency Voltage-to-Frequency Converter (VFC)
silicon fuzz
Rolling Shutter Motor Control



Top