Suggested by Raytheon in 1967 documentation this circuit uses a lightbulb and LDR optical coupler of the time. The transistor determines the maximum current.
Based on an Analog Devices LTC1540, this circuit consumes only 50 uA, serving to monitor the...
This circuit was found in a 1980s documentation. The diodes may be general purpose diodes such as 1N34...
We found this digital timer circuit in a 1994 publication. The power is supplied by 12 V, which is the...