Introduction
Building a small transistor amplifier circuit is a simple yet effective way to amplify weak signals. To create this circuit, you need a few electronic components, a breadboard, and a power source. In this tutorial, we will walk you through assembling a basic transistor amplifier circuit using bipolar junction transistors (BJTs). By understanding how the circuit works and what each component does, you will gain hands-on experience with electronics and expand your skill set.
We will focus on the design and assembly of a basic transistor amplifier circuit. By the end of this guide, you will have a solid understanding of how transistor amplifier circuits work and can build one on your own.
Hardware Required
You will require the following hardware for the Small Transistor Amplifier Circuit.
| S.no | Components | Value | QTY |
|---|---|---|---|
| 1 | Polar capacitor | 47, 470uF | 1, 1 |
| 2 | Resistor | 1k, 100k | 1, 1 |
| 3 | Transistor | 2N2222, 2N2905, 2N3053 | 1, 1, 1 |
| 4 | Diode | 1N4148 | 2 |
| 5 | Speaker | 25ohm | 1 |
Circuit Diagram
Working Explanation
This Small Transistor Amplifier Circuit is a compact circuit commonly found in car radios. It consists of a source stage that is biased to distribute the source voltage evenly between two matching output BJTs. The diodes between the bases moderate the bias in conduction.
To maintain stability, a 3.3-ohm resistor is placed in series with the emitters of the output driver transistors. This reinforces the bias current and reduces the risk of variation due to temperature or transistor/diode changes.
When the bias current increases, the voltage between the emitter/base decreases, reducing the conduction. The circuit’s input impedance is approximately 500 ohms, and the voltage gain is around 5 with an 8-ohm speaker connected. The speaker experiences a voltage fluctuation of 2 volts with minimal distortion, and the power output is in the 50 milliwatt range. If the supply voltage were to increase and heat sinks were added to the output driver transistors, the power output would increase. The circuit draws approximately 30 milliamps from a 9-volt supply.
Final Words
The Small Transistor Amplifier Circuit is a compact and efficient solution for amplifying sound in car radios. It has been designed to overcome potential stability issues and deliver consistent performance, even in varying temperatures. The circuit is a testament to the ingenuity of engineers who have managed to pack so much functionality into such a small and compact design.
We hope you enjoyed reading about this fascinating circuit and learned something new about how it works to enhance your audio experience. Happy learning!
