Audio limiter (CB7395E)

This circuit cuts the audio spikes. It was found in an English publication from the 1980s. Transistors are general-purpose used today.

Mini amplifier 2N301 (CB20529E)
This 200-mW amplifier uses one of the first commercial power transistors. The circuit is from a...
Frequency Divider Using the 4017 (CB209E)
Decade counters, such as the 4017, can be cascaded as sourcing signals with the frequency divided...
Dial monitor (CB5999E)
We found this circuit in an American 1980s documentation. The circuit uses a piezoelectric transducer...