We found this circuit in a 1965 General Electric manual. The controlled load depends on the Triac and the 100 uF capacitor delay time.
An interesting timer is shown in the figure, using one of the 4 NAND gates of the integrated 4001....
General Electric suggests this circuit in a 1980s documentation. The operational of the time is...
This simple adjustable source uses a PNP transistor that can be the BD136 for even slightly higher...