Bipolar transistor cookbook series#

Basic construction (a) and symbol (b) of pnp transistor. If it uses a p-n-p structure, as in Figure 2(a), it is known as a pnp transistor and uses the symbol in Figure 2(b).įIGURE 2. Basic construction (a) and symbol (b) of npn transistor. If it uses an n-p-n construction sandwich, as in Figure 1(a), it is known as an npn transistor and uses the standard symbol in Figure 1(b).įIGURE 1. The term “bipolar” means that the device is made from semiconductor materials in which conduction relies on both positive and negative (majority and minority) charge carriers.Ī normal transistor is made from a three-layer sandwich of n-type and p-type semiconductor material, with the base or “control” terminal connected to the central layer, and the collector and emitter terminals connected to the outer layers. BIPOLAR TRANSISTOR BASICSĪ bipolar transistor (first invented in 1948) is a three-terminal (base, emitter, and collector), current-amplifying device in which a small input current can control the magnitude of a much larger output current.

Bipolar transistor cookbook series#

The remaining seven parts of the series will present a wide range of practical bipolar transistor application circuits. This opening episode concentrates on basic transistor theory, characteristics, and circuit configurations.

In its discrete form, it can function as either a digital switch or as a linear amplifier, and is available in many low, medium, and high power forms. The bipolar transistor is the most important “active” circuit element used in modern electronics, and it forms the basis of most linear and digital ICs and op-amps, etc.