- #1
- 3,486
- 1,165
Hi everyone..I'm trying to build a Joule Thief circuit operating on a 1.5V cell. Which transistor should I use? I have BC547 but I'm not sure it will work...Suggestions are welcome..
A Joule Thief is a simple electronic circuit that can take a low-voltage input and boost it to a higher voltage output. It is often used to power small electronic devices, such as LED lights, with a single battery.
A Joule Thief works by using the inductive kickback from an inductor to create a higher voltage output. This is achieved by rapidly switching the flow of current through a transistor, which causes the inductor to build up a magnetic field. When the transistor turns off, the magnetic field collapses, creating a spike in voltage.
The most commonly used transistor for a Joule Thief is the 2N3904 NPN transistor. However, other transistors such as the 2N2222 or PN2222 can also work well. The key is to use a transistor with a high current gain (hFE) and a breakdown voltage (BVCEO) of at least 30V.
Yes, a MOSFET (metal-oxide-semiconductor field-effect transistor) can also be used in place of a transistor for a Joule Thief. However, it is important to choose a MOSFET with a low threshold voltage, typically less than 3V, and a high drain-source breakdown voltage (BVDSS) of at least 30V.
When selecting a transistor for a Joule Thief, it is important to consider its current gain (hFE), breakdown voltage (BVCEO), switching speed, and power dissipation capabilities. It should also be able to handle the current and voltage requirements of your specific circuit. Experimenting with different transistors and adjusting the circuit components can help you find the best combination for your needs.