This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the lighting point of the LEDs. The circuit is for 12 V automotive batteries.
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...