We found this circuit for receiving shortwave on a mediumwave radio in a 1986 Hobbyst Electronics PE. The circuit has the received band given by T1 which can be an FM IF.
This circuit emits an audible signal when the mains voltage ceases. The circuit is from a 1973...
We found this circuit in a 1966 RCA manual. The integrated circuit is unusual, and the Triac must...
Short duration pulses or "clicks" can be generated with the circuit seen in the figure. The...