Standard Bipolar Transistor
in standard NPN and PNP characteristic , Darlington and Prebiased Transistors.
The bipolar Transistor is a current controlled amplifier. A small current (drive current) on the Base-Emitter-Circuit controls a large current (load current) on the Collector-Emitter-Circuit.
General use as switches and amplifiers
The amplification factor is 20 – 1000
Darlington multiply the DC current gain.
The drive current makes the transistor to a switch.
Prebiased Transistors are general purpose Transistors with Built-in Resistor Network to made the PC-Board smaller.