Open collector output and open drain output utilize a transistor as a switch that either disconnects or connects an integrated circuit (IC) output pin to ground, instead of outputting a specific voltage or current.
An open collector output processes an IC's output through the base of an internal NPN transistor, whose collector is an external output pin. The emitter of the NPN transistor is internally connected to ground. The open collector internally forms either a short-circuit (technically low...