Found in a Raytheon transistor manual from the 1950s, this circuit uses one of the first commercially available transistors, the CK722. The circuit is for using a small speaker as a microphone.
This high-speed circuit was found in 1980s Linear Technology documentation. The circuit makes use...
The transistors of this amplifier for 8-200 headphones may be the BC548 or equivalent to replace...
The frequency of this pulser depends on the capacitor and the characteristics of the relay. The...