Solder the Circuit Together on a Circuit Board 6. Select a Power Source 7. Next Prev. Step 3: Wind the Toroid. Step 4: Prototype the the Circuit on a Breadboard. Step 6: Select a Power Source.
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This results in the transistor turning off". I don't think so, I think the induced current in the base coil is complementary to the current flowing into the base of the transistor from the battery. Then, The transistor will reach the saturation mode faster. I Knew that from the small dots on the transformer symbol. When the transistor is fully on at saturation mode , The collector-emitter junction has a very small resistance. Also, at saturation mode, There is no change in the current flowing through the collector coil, so there is no reactance and the resistance of the collector coil is very small.
Now, All the current of the circuit is flowing from the collector to the emitter through collector coil because that branch path has a very small resistance relative to any other path.
The branch path from the battery to the base has about 1K resistance. This allows less electricity to travel through the second coil. A drop in the amount of electricity in the second coil induces a negative amount of electricity in the first coil.
This causes even less electricity to go into the base of the transistor. Steps 7 and 8 repeat in a feedback loop until there is almost no electricity going through the transistor. Part of the energy that was stored in the magnetic field of the second coil has drained out. However there is still a lot of energy stored up. This energy needs to go somewhere. This causes the voltage at the output of the coil to spike. The built up electricity can't go through the transistor, so it has to go through the load usually an LED.
The voltage at the output of the coil builds up until it reaches a voltage where is can go through the load and be dissipated. The built up energy goes through the load in a big spike. An article titled One-Volt L. D — A Bright Light by Z. Kaparnik, and published in Everyday Practical Electronics, features a circuit that uses the same principles as the initial Joule Thief circuit in order to create high voltage pulses.
The name Joule Thief is coined by Clive Mitchell and a tutorial is published on his website. Clive's variation includes a smaller resistance than the original circuit published in the EPE magazine. How can a Joule Thief circuit be made? How can the Joule Thief circuit be optimized or modified? What are the applications of this circuit? What are the disadvantages of using a Joule Thief circuit? What are some alternatives to the Joule Thief circuit? How does the supercharged Joule Thief circuit have such a high efficiency?
Article Info Contributed by 2 authors Last updated on Article Versions 11 , Chat Room. You are editing an existing chat message. Summary Discussion How does the Joule Thief circuit work?
The voltage output from a joule thief circuit. X-axis is time in seconds and Y-axis is potential difference in volts Source: VandeWettering
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