This circuit is from an Electronics World of 1967. The described calculations can be applied to equivalent circuits with modern transistors.
This circuit uses a GE optical coupler. Equivalents can be tried. The circuit is from the GE...
This simple circuit connects in external battery to a load when the AC Power line fails. S1 can be...
April 2017 - Mouser Electronics already has in stock the new HMC8400, Analog Devices low noise...