Portable Lab (T1583E)

This circuit was obtained from a Radio Electronics from 1947. It is a multi-utility circuit for the workbench with valve devices.

Signal Injector (CB5889E)
This simple injector circuit can actually be powered by voltages from 3 to 9 V. The frequency is...
Simple Timer Using the 555 (MSB123E)
This simple timer can be used in many applications such as egg timer. The LED glows up when S1 is...
CMOS Touch Key with Lock (CB1275E)
This circuit locks after a short touch on the sensor. The circuit can be powered by voltages from 5...