This circuit was found in ancient American documentation. It provides a 70 Vpp signal at frequencies up to 100 kHz. Observe the high supply voltage.
The integrated circuit used in this 1986 wireless microphone is not very common today. The L1 coil...
This circuit is from a 90s Radio Electronics. The resistors must be precision types and the...
This is Heathkit's CW-30, a miniaturized 4-transistor receiver for the citizen band or 11 meters. The...