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What does a joule thief do?
A joule thief is a minimalist self-oscillating voltage booster that is small, low-cost, and easy to build, typically used for driving small loads. This circuit is also known by other names such as blocking oscillator, joule ringer, vampire torch.
How efficient is joule thief?
So designed the Joule thief was able to produce 34 V voltage measured on the collector node of the NPN transistor (2N2222) without any load, when supplied by 1.2V AAA battery (filterd with 2.2uF capacitor).
What are the two types of astable blocking oscillator?
Here, two types of astable blocking oscillators are considered: a diode-controlled astable blocking oscillator and an RC-controlled astable blocking oscillator.
What is another name for a blocking oscillator?
pulse oscillator
A blocking oscillator (sometimes called a pulse oscillator) is a simple configuration of discrete electronic components which can produce a free-running signal, requiring only a resistor, a transformer, and one amplifying element such as a transistor or vacuum tube.
What is the purpose of the joule thief circuit?
What is joule thief circuit? Joule thief circuit is an oscillatory voltage booster which can boost small amount of voltage around 1V or less to a usable voltage to drive small loads like LEDs. The joule thief circuit extracts almost all energy from a standard single cell.
How big can a Joule Thief led be?
A Joule Thief with a 1k resistor and a small transistor, known as a ‘small signal’ transistor will put out up to 100 milliwatts to a standard 5mm diameter white or blue LED.
What kind of diode do I need for joule thief?
1N4007 diode will also work but to get most out of your circuit, a germanium diode like 1N4148 is recommended. The primary side of the transformer is short circuited; this will increase the brightness of the LED.
Which is more efficient, the joule thief or the resistor?
The efficiency of the three LEDs was 66.8 percent. For the Joule Thief with the same LED current, the supply current was 76.8 mA, and the efficiency was 50 percent. The conclusion is that the resistors are more efficient and use less current than the Joule Thief.