This Vox or sound activated relay was found in an American documentation from 1975. Equivalent transistors can be used, and the SCR can be a TIC106. The relay is according to the supply voltage.
This non-inverting AC amplifier was found on a Popular Electronics. The setting applies to any...
This circuit supplies 5 V from two AA batteries. The output current is 4 mA, resulting in an 11 mA...
With this regulator we can have currents of up to 4 amps with 5V at the output. The transistor can be...