Stereo FM Transmitter (CB8459E)

This circuit was found in a 90s Radio Electronics. The FM encoder or multiplexer is an uncommon component today.

Audio expander (CB8507E)
Based on the Philips TDA3810N, this circuit was found in an 90s Electronics Now. The circuit has two...
Sound intensity indicator (CB23649E)
This simple circuit does not use active components and uses a small speaker as a microphone. The...
Car Power Amplifier (CB17259E)
This power amplifier configuration can be used in a public address system (ads) in the car. The...