This configuration similar to many of this site was found in 1965 General Electric documentation. Modern equivalent transistors can be used. LEDs can be used.
In this case, the output will be activated (1) when both inputs are deactivated, that is, neither one...
Found in Radio Electronics, this simple indicator circuit uses general-purpose transistors common today....
This optical coupler for short distances is powered by 12 V which is the voltage of the lamp and...