How to make a Joule Thief Circuit

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Introduction

In electronics, the joule thief circuit is the voltage booster circuit that converts the input voltage into a greater periodic voltage value. You may have known this before, but do you know that joule thief circuits have some other interesting names too? Interesting, right? South it is also popular as a joule ringer, blocking oscillator, and vampire torch. To know how these names get fit into the circuit you need to read the entire article. Thus, in this tutorial, we are going to discuss How to make a Joule Thief Circuit.

Although you can make this circuit in various other ways. But, in this article, we are trying to take a cheaper approach. So, we will make the circuit by using two transistors and some other simple components.

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2$ PCB Prototype

Hardware Components

The following components are required to make Joule Thief Circuit

S.no	Component	Value	Qty
1.	PCB	–	1
2.	Transistors	BC547	2
3.	Ceramic Capacitor	220pF	1
4.	Resistor	22K, 330 ohms	1, 1
5.	LED	–	1
6.	Coil	100uH	1
7.	Battery cell	1.5V	1

BC547 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of BC547

Joule Thief Circuit

Working Explanation

This Joule Thief Circuit works by the 1.5V battery cells. When you apply the supple, current passes through the wire’s coil, and a magnetic field gets generated around that coil. Consequently, it generates a greater amount of electricity in the coil. This triggers the base of transistor Q2 and hence also opens the collector-emitter channel. Now, this built-up energy of the circuit can’t pass through the transistor so it flows through the load, that is LED. Hence LED glows.