Tone Oscillator (CB22066E)

Found in old documentation, this oscillator with the LM380 produces an audio tone in a speaker. Frequency is set in VR1.

Residential Alarm (CB17228E)
This simple alarm circuit was found in a 1998 documentation. When the sensors are activated, the...
Microphone balanced amplifier (CB9388E)
This circuit was found in an old American documentation. The integrated circuit used is uncommon...
Increasing the voltage of a fixed regulator (CB8476E)
Found in a 90s Electronic Design, this suggestion to have a higher voltage in a fixed regulator...