Solar intercom (CB20503E)

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

Linear Amplifier from 25 Hz to 120 kHz (CB11989E)
This simple amplifier stage with a transistor has a linear response from 25 Hz to 120 kHz. The...
Class A 10 W Amplifier (CB13678E)
The output transistors can be the TIP41 and the BD135 and BD136 drivers. TR1 can be a BC558 and...
Thermostat (CB25731E)
The general-purpose thermostat shown in the figure uses a high-resistive thermistor as a sensor....