Microphone 8 W amplifier (T369E)

This circuit was found in the 1961 RCA tube manual. The 4-tube circuit is suitable for microphones and record players with high impedance input.

Ultrasonic Oscillator (NI008E)
The 50 kHz signal generated by this circuit is applied to a low impedance inductive transducer. A...
Amplifier with the 4049 (CB4770E)
This different audio amplifier was found in a 90's Electronic Design. The circuit uses components...
Analog-to-Digital Converter – 555 (NI024E)
This circuit converts a resistance in the range between 1 k ohm and 1 MΩ to a signal in a...