# Peltier Joule Thief. Start Up Project 37

You know, we can light a 1 watt LED without a battery! Peltier will give “Free Electricity” for that. When we heat the Peltier with flame, hot water or a hot object, it starts to generate current. Its voltage can be around 1.5V when the heat is above 60 degree. But this 1.5V is not sufficient to light even an ordinary LED that requires 1.8V minimum. 1 watt White LED requires 3.6V. Then how? We can add a Joule Thief circuit for that. A Joule Thief circuit is a self oscillating circuit that increases the input voltage as low as 700 mV to 4-5V. So if the Peltier is connected to a Joule Thief and heated, Joule thief will amplify the voltage to light the 1 watt LED. Let us check this.
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# Button Torch. Start Up Project 12

Probably, this may be the smallest 1 Watt LED Torch working on a Watch battery. It is the “Micro Joule Thief circuit” that is made as compact as possible. It rests on a heat sink of the 1 watt LED and powered by a 1.5V Button Cell. We can make different types of Joule Thief circuits and this experimentation is to make it as small as possible. Try it.
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# Free Energy from Computer Fan. Start Up Project 11

It is not a wonder but a real fact that, we can light a 3 V 1 Watt LED without any battery power. You can harvest that much “Free Energy” from a Computer cooling Fan that is resting in the Junk box. A Computer Fan generates around 1.5 Volts with a current of around 80 mA during its full speed rotation when coming close to a Table Fan. By adding a Joule Thief circuit, we can boost this 1.5V to around 4 volts. Well, that is a good idea. When the Computer Fan is close to a Table fan, the forcing wind from the Table Fan starts to rotate the Computer fan in its full speed. The 1.5V thus generating from the Computer fan appears in its connecting wires. Joule Thief takes this voltage and boosts it to 4V. It is sufficient to light a 3 V 1 Watt LED. The Computer Fan used in the project is an original one without any manipulation and not like the one found in some videos with a hidden battery. Let us see the “Free Energy Magic”. You can also name it as “Wind Power Project”.
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# Joule Thief Circuit. Start Up Project 5

You can turn on a 3 Volt LED just using 1.5V Battery. It is the Joule thief circuit doing the trick. Joule thief circuit is a self oscillating voltage booster used to drive light loads like LED. The name Joule thief is given to the circuit because; it is stealing the Joule or energy from the battery. That means, it is extracting energy even from an almost dead battery to power a load. Try it. This is one basic circuit you should know as a starter in electronics.
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# Make a Joule Thief. Design Note 20

Joule thief circuit is a self oscillating voltage booster circuit that gives high volt from low volt, say 3 volt from 1.5 volt. So by exploiting this property, we can light a 3 volt LED using 1.5 volt pen cell or charge a mobile phone from 3 volt solar cell or two 3 volt pen cells. It is called as “Joule thief” because it is stealing energy or joules from the battery. Let us design the Joule thief circuit.