This 12 V x 2 A regulator was found in 1965 Delco Radio documentation. The circuit uses transistors from that time. The input voltage can vary by 15% around the indicated value.
This half-wave regenerative control was found in an old RCA manual. The circuit can be designed...
I found this circuit in a documentation about thyristors from the 70s. The circuit uses a diac...
Up to some minutes intervals can be obtained from this circuit. The circuit can use a lamp (or...