This timer, like the previous circuits, uses a currently uncommon integrated circuit. The time is given by capacitor C1 and R2 which has the range of values indicated in the diagram.
This circuit is from the 80's documentation. The integrated circuit is from the time but can be...
This circuit was found in old publication from 1958. The circuit uses germanium transistor, common in...
This version is from an old 80's documentation. The SCR can be the TIC106 and the unijunction...