MOSFETs come in N-channel and P-channel types. For the P-channel, conduction occurs when the gate voltage is at least 5V lower than the drain voltage, while for the N-channel, conduction occurs when the gate voltage is at least 5V higher than the source voltage. The choice between N-channel and P-channel depends on the voltage difference between the drain and source.
N-channel enhancement types are commonly used in daily applications due to their low thermal resistance and low power dissipation. P-channel types are less common due to their higher cost, higher on-state resistance, greater heat dissipation, and lower efficiency. Their only advantage lies in certain scenarios where driving gate voltage is critical for fast switching.
Differences between MOSFETs and Bipolar Junction Transistors (BJTs):
- BJTs are current-controlled, while MOSFETs are voltage-controlled.
- BJTs are generally less expensive than MOSFETs.
- BJTs tend to have higher power losses compared to MOSFETs.
- BJTs are commonly used in digital circuitry, while MOSFETs are preferred for high-frequency, high-speed circuits, high-current applications, and automotive electronics.
Applications of MOSFETs include power tools, industrial switching power supplies, charging stations, unmanned aerial vehicles (drones), electric bicycles, energy-efficient bulbs, and LED lighting power supplies.