Arduino Forum

Using Arduino => LEDs and Multiplexing => Topic started by: murdocx on Jan 30, 2013, 05:29 pm

Title: dimming leds with tip122 and voltage variable
Post by: murdocx on Jan 30, 2013, 05:29 pm
Im trying to dimming two LEDs in parallel with a power supply of 3-48V variable and 1.4A constants with a TIP122. If I use a 3.7V battery I have no problems, but the supply give me 48V and tip begins heating extremely, but leds only needs 3V. This is like transistor demands all power capacity. Im using a 2k2 resistor on the base.
any idea? thanks
Title: Re: dimming leds with tip122 and voltage variable
Post by: runaway_pancake on Jan 31, 2013, 03:49 am
Schematic?

[Draw it out on a sheet of paper, take a picture of that and include it as an attachment.]