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Unread 08-07-2012, 00:40
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Ether Ether is offline
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Re: Turning LEDs on/off

Quote:
Originally Posted by rsisk View Post
When I switched to the signal tonight, there was no light when I set the DIO to true or false. When the LED is on power and ground, it comes on
Sounds to me like the output impedance of the DIO signal line is too high to provide enough current to light the LED (as mentioned in my earlier post).

Disconnect your LED circuit and put a voltmeter (a cheap $10 one will do) between signal and ground at the DIO output. Flip the DIO true/false and confirm that you are getting 5 volts and zero volts.

Now connect your LED circuit (leaving the voltmeter connected between signal and ground). My guess is that you will no longer see 5 volts. The load from the LED acting on the impedance of the signal source will drop the voltage below that necessary to provide the current to light the LED.



Last edited by Ether : 08-07-2012 at 00:43.