Led lights

[TeddyTyler]

I just insatalled two leds in series with a 10 ohm resister in parallel with my speed 600 motor and a 7 cell 1400mha batrtery pack , Amazingly when I give the the speed control more speed the leds get bright at a point then go a little dimmer , why dont they get brighter, the motor goes faster? you can email me if you choose ronplanes@cs.com

[NightSwan]

What kind of LED's are they?

If they're standard (1.2V / 20mA LEDS), you're overloading them..

resistor-calculation :

R = (Vbatt - Vled) / Iled =~ 360 Ohms.

I've also experienced that LEDs, when overloading them, get brighter untill a certain point, and then start to loose brightness at higher voltages. (and after a while snap or start to smoke)

I'd suggest using a larger resistor in that case.


Hans

[Mr.RC-CAM]

Yup, you're going to kill a typical LED with that low value current limiting resistor. The mentioned 360 ohms sounds fine, but given the pack's V-drop under load (motor current), I would think 300 ohms would safely offer good high-speed brightness.

If you are using the new high-Lux LEDs, the resistor value will be much different. A data sheet review is in order.

[TeddyTyler]

I think you got the answer about the resistor I will change it thanks

[Foamtoyz]

Don't forget that different color Led's have different forward voltages and need different resistors too.