Transistor application circuit

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit.

The above simulation is based on a circuit that actually works. The transistor uses C1815(general-purpose NPN switching transistor). The resistance connected to the base is 100kΩ, and the resistance connected to the emitter is 100Ω.