MOSFETs

A voltage-controlled switch built for efficient, high-current jobs.

A MOSFET is another kind of transistor, but instead of a small current controlling it, a voltage on its "gate" leg does. Because almost no current flows into the gate, MOSFETs waste very little energy switching — which is why they dominate modern power electronics.

• Three legs: gate, drain, source (roughly equivalent to a BJT's base, collector, emitter).
• Great for switching motors, LED strips, and other higher-current loads directly from a microcontroller.
• Always check a MOSFET's datasheet for its gate threshold voltage — some need more than 3.3V or 5V logic can supply.

You won't need MOSFETs for your very first projects, but they're worth knowing exist once you outgrow small BJTs.