This circuit is from an 80's technical newsletter. The circuit can use any general purpose transistor and its power supply can be changed with a resistive divider to use a single 9V battery.
Found in a Popular Electronics from the 1990s, this circuit uses components from National...
This combination key or code key was found in old documentation. The consumption is very low, and...
This circuit was found in a European documentation from 1964. The circuit makes use of components of...