This circuit is from a 1976 amateur radio manual. The transistor can be the BD136 and the frequency adjustment is done in a potentiometer. The supply can be done with voltages from 6 to 15 V.
This circuit is based on the voltage drop of the diodes in conduction, in the order of 1.6 to 1.7...
Found in older documentation this setting applies to modern components, noting that the power...
This simple timer can be used in many applications such as egg timer. The LED glows up when S1 is...