I am trying hookup a 10mm superbright led to a wall wart that is rated output 9v, 300ma. I used a 470 ohm resistor for this connection but .the wire feel a little warm to me. When working with wall warts how does one compute the resistors need for the wall wart strength. Do we go solely by the output info or what? thanks in advance for your help. BTW if I add more leds later is there a simple design for a brightness adjustment...i'm trying to make a sub stage microscope light source. While one bulb works well on the lower power I might need to add more in order to view the higher magnifications and I'd like to be able to adjust the led brightness.
14 years ago