Transistor as a switch

Two-BJT implementation of Two-Input OR Logic Gate. Switch input for observing the behavior in Interactive Simulation. Vin1 and Vin2 are the input signals. The output is at the junction of Ropu and the collector of the NPN transistor. Notes: Depending on the transistor used and the voltage level of Vin2, the NPN transistor may need protection against reverse breakdown of the base-emitter junction. I saved the circuit with the switches in the opposite positions so that the graph will have an appropriate initial scale.