looking for a mosfet with high efficiency

Thread Starter


Joined Jun 3, 2009
HI everybody!

I am seeking a high efficiency mosfet for a LED lighting project.

TO-92 or T-220 casing preferred or if SMT/SMD the larger the better. The load is 150ma @ 12v. Heat dissipation is not a concern. Input frequency is 120Hz.

Currently I am using IRF510 but the efficiency is about 85% which greatly dims the LEDs in this project. =/ Increasing the input voltage is not a current option.

My ignorance leads my drawing a blank on how to calculate a mosfet's with out physically testing the voltage differences.

Any leads to finding something around 95%+?



Joined Dec 20, 2007
When you use a resistance like a Mosfet to dim an LED, when the LED is at half the max current then the efficiency is near 50% for any Mosfet.

The spec's for a Mosfet vary too much to easily control their resistance.

You forgot to post your schematic for me to see the forward voltage of your LEDs, how many are in series and the current-limiting resistor for max current.