Found in 1967 Raytheon documentation, this circuit uses a company coupler consisting of a lamp and an LDR. The transistor is according to the load current.
This circuit was found in a General Electric documentation from 1965. The circuit is full wave for...
This is another quick adder that we found in an Electronic Design from the 80s. It also applies to...
This circuit uses two sensors that are placed at the intersection of a miniature railroad, causing the LED...