This is a simple and easy designed circuit which is used to test the continuity. We know that continuity tester will used to test whether there is continuity or connection between two components. Here ...
This simple but clever continuity tester sports two LEDs: RED LED = circuit resistance is < approx 10K, GREEN LED = circuit resistance <10Ω. It consumes approx 8mA from a 9V battery. When not ...
A. F. BUBNS, in an article on testing of the crossbar system of telephony (Bell Lab. Rec., 20, No. 9 ; May, 1942), points out that in dialling systems a talking connexion is established through a ...