This simple timer with unijunction transistor was found in an old American technical documentation. We can use 2N2646 for the unijunction and BC548 for the transistor.
Found in a 1970 publication by General Electric, this circuit makes use of a mobile...
This circuit switches on an external load after a certain interval given by the capacitor. The...
Using common SCRs like the TIC106, this circuit is loaded with incandescent bulbs, but can be...