Solar intercom (CB20503E)

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

Crystal Oscillator Using an Inverter (CB119E)
This page shows a crystal oscillator for 2 MHz. Other frequencies can be produced depending on the...
Monostable TTL 7400 (CB9424E)
This circuit is from a 1970 publication. The time constant is given by 1.3R x C where R is the...
4 W amplifier TDA1904 (CB15219E)
The supply voltage range of this circuit ranges from 4 to 20 V and the power depends on the chosen...