We found this circuit in a 1991 Hobbyst Electronics. The circuit makes use of an unusual transducer today. It is a piezoelectric buzzer that can eventually be replaced by an equivalent configuration.
This circuit generates a frequency modulated tone with excellent power. Other power MOSFETs can be...
This circuit has a sensitivity of 200 mV providing an RMS power of around 4 W for a load of 8 ohms...
This filter was obtained from Radio Electronics from the 80's. The configuration applies to any...