THE MAGAZINE FOR COMPUTER APPLICATIONS
Circuit Cellar Online offers articles illustrating creative solutions
and unique applications through complete projects, practical
tutorials, and useful design techniques.

ANALOG BASICS

Transistor Signal Amplification

by James Antonakos

Start ý In The Beginning There Was Biasing ý Getting Signals In And Out ý The Big Capacitor ý A Close Look Inside • Loading the Amplifier • Is This the Right Frequency? • Yes, But Op-Amps are Easier • Sources and PDF

This month, letýs take a short break from ones and zeros and spend some time reviewing the analog side of the electronics world. In this article, Iýll examine the common emitter transistor amplifier, component-by-component, and show you how the circuit performs its magic.

THE CIRCUIT

Figure 1 shows a fully designed common emitter amplifier. Four resistors, three capacitors, plus an NPN transistor are all that is needed to construct the amplifier. Everything is powered from a 12-VDC power supply. The ground is on the emitter side of the transistor circuit, making the emitter common to the input and output, hence the name common emitter.

Figure 1ýTake a look at the BJT bypassed common emitter amplifier.

NEXT