This circuit triggers by choosing the higher of two voltages. The circuit is from a 1964 Electronic Design. The transistors are of the time and can be replaced by current equivalents.
April 2017 - Mouser Electronics already has the MAX4007 from Maxim Integrated in its inventory, an...
This circuit was obtained from an English magazine from 1979, but can be easily assembled today...
Found in a 1978 publication, this circuit uses germanium transistors and drives a small 20 to 50...