Design and Implementation of Two-Stage Amplifier using 2N2222 Bipolar Junction Transistors (BJT)

Bagus Hanindhito¹, Daniel Maruahal Simarmata²
Department of Electrical Engineering, School of Electrical Engineering and Informatics
Institut Teknologi Bandung, Indonesia
Email : ¹hanindhito@bagus.my.id, ²danielmaruahal@gmail.com

Abstract—Amplification is a fundamental part in modern electronic circuits. An amplifier can amplify signal in specific frequency and with specific gain (i.e. voltage gain, current gain). An amplifier can be implemented using discrete components (i.e. BJT, MOSFET) or inside an integrated circuit. During the design process of an amplifier, there are several figures of merit that must be taken into account: gain, frequency range (bandwidth), efficiency, linearity, SNR, slew rate, and stability.

In this project, a two-stage amplifier will be implemented using two BJT NPN 2N2222 to give 20 times of voltage gain, 600Ω of input resistance, and 16Ω of output resistance. The amplifier should have a good linearity and efficiency when the frequency range of input signal is around 1kHz. Moreover, the amplifier should deliver highest efficiency with smallest number of components (i.e. resistor, capacitor) used.

The amplifier consists of two common-emitter stages. The first stage of common-emitter will be the workhouse where most of the voltage gain will be obtained from this stage whereas the second stage of common-emitter will not be deliver high gain, instead it will be used for inverting signal and adjusting the output resistance.

SPICE and Multisim will be used to help simulating the design of the amplifier before implementing it on a breadboard for real world test. If the real world test gives very good result compared to its initial specification, a printed circuit board will be designed for final product implementation.

Index Terms— amplifier, amplification, BJT, common emitter