Solar intercom (CB20503E)

This circuit can be used in demonstrations or science fairs. The circuit uses headphones and can be powered by solar cells.

Capacitance multiplier (CB7803E)
We found this circuit in an old Popular Electronics. The circuit can be applied to other...
27 MHz Converter (CB16876E)
With this circuit it is possible to receive the signals from the 11-meter band (27 MHz) in a...
60 V Bidirectional Motor Control (CB19568E)
We found this circuit in an American publication from the 90s. The transistors must be provided with...