
Active components 67
on by a positive voltage at the gate of the MOSFET
structure. The latter is brought out as the gate
terminal, in place of the Ρ base region of the NPN
section. This results in a high-voltage, high-current
device capable of controlling kilowatts of power.
Whilst the steady state gate current is zero, a
low-impedance drive is required to turn the device
on rapidly, owing to the need to charge the
effective gate input capacitance quickly.
The triode AC semiconductor switch or triac is a
bilateral-controlled switch and can thus be used to
control power in AC circuits. It can be triggered on
by either a positive or a negativ ...