BJT amplifier is one of the most often used electronics circuit. It is used in audio circuits, RF circuits, oscillator, mixers etc. So as an electronics designer when prototyping some electronics circuits that involves amplifiers on breadboard it is useful to have BJT amplifier module or breakout board which can be simply fitted onto a breadboard. Creating such module saves time. So here a BJT amplifier breakout board module is build on a perfboard which is as shown in the picture below.
The BJT amplifier is based on 2N2222 general purpose NPN transistor. The amplifier is class A amplifier build with voltage divider biasing which is the best biasing method. Other than the transistor some resistors and capacitors are required so it is easy to make. The following shows the circuit schematic of the amplifier.
The resistors R1, R2, RC and RE are used to bias the transistor. The capacitors C1 and C2 are coupling capacitors and the capacitor C3 is bypass capacitor. The values of the resistors depends upon the input and output voltage and current requirements. While the value of the capacitors depends upon the frequency of operation. These values can be selected using online BJT amplifier online calculator.
A simple demonstration of working of this BJT amplifier module is illustrated here. The input signal of 440Hz and 100mV is fed into amplifier and the output is amplified in magnitude. We used here audio signal generator and oscilloscope display of a PC soundcard oscilloscope.
Below picture shows the input signal from signal generator.
The picture below shows input signal graph.
And the picture below shows the amplifier output signal.
The following video demonstrates the working of the BJT amplifier module.
Tags:
amplifier
