A transistor has three legs. A small amount of current/voltage on the "Base" (Gate) controls a large amount of current flowing between the "Collector" and "Emitter" (Drain and Source).
Dimming lights or controlling the volume on a speaker. 2. Capacitors: The Energy Sprinters electrical components and their functions
Diodes have a "forward voltage drop" (usually ~0.7V for silicon). They don't conduct until the voltage exceeds this threshold. A transistor has three legs
Require physical movement to open or close a circuit (like a light switch). electrical components and their functions