Remote control tester (CB7823E)

This circuit from a 90s Electronics Now, uses a 4010 gate as a signal amplifier. The circuit triggers an indicator LED.

Automatic Headlight Control 555 (CB25502E)
This circuit was found in the September 1992 issue of Radio Electronics magazine. The circuit does...
Power grid voltage failure indicator (CB7013E)
Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the...
Instrumentation Amplifier (CB20989E)
This ultra-low noise amplifier and simple power supply was found in Analog Devices documentation from the...