Workspace Goal
This workspace demonstrates a basic low-side NPN switching circuit. The push button drives base current through RB, the transistor turns on, and collector current flows through R_LED and the LED load.
The base is held low through RPD, so the transistor stays off and the LED path does not conduct.
Base current flows through RB. Q1 turns on and allows current to move from collector to emitter, lighting the LED.
Vcc, SW1, RB, RPD, R_LED, LED, and Q1 2N3904.