We found this circuit in the magazine Eletcronics Now of July 1994. The power supply is according to the relay and the transistor can be any general purpose one.
The circuit shown has the component values calculated for a frequency of 1 kHz. TL064 can also be...
This circuit can either directly supply a piezoelectric transducer (BZ) or a stage with a...
This circuit is suitable for SSB modulation and was obtained from an amateur radio documentation from...