operation of a normal transistor



3 terminals; base, common, active


common connected to negative supply, (possibly through a resistor, other transistor, etc.)

active connected to positive supply, (possibly through a resistor, other transistor, etc.)


base, input

with no input, no current flows though active to common connection

with input voltage over 0.7V, current flows through active to common connection

current flow is a multiple of the base-to-common current, up to 500 times.

when fully 'switched on', the active-to-common resistance is very low.




type 2

same as a normal transistor, with the opposite polarity at all terminals.




fet

operates with pulses of current,

	range min freq to max freq

	normal trans, operation 0 to max freq
