Old 03-11-2012, 04:25 AM #1
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Default Driver / no driver

applying power directly to leads on a diode vs using a driver will this damage the diode is a driver necessary (using a constant source variable power supply).

tks


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Old 03-11-2012, 04:37 AM #2
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Default Re: Driver / no driver

*Edit* sorry I saw your "using a power supply" part

As long as you can limit the current that is delivered to the diode it is safe

Last edited by Fretwrecker94; 03-11-2012 at 04:38 AM.
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Old 03-11-2012, 04:59 AM #3
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Default Re: Driver / no driver

Here is how I do it. With the diode not connected to the power supply turn it on and set the voltage just under the max forward voltage of the diode. You may need to find a graph for your diode to see what that is. For 445 diode about 4.5V would be good for starters. Next turn the current to zero. Turn off the power supply and short the output leads together. Then connect your diode and turn on the power supply. Slowly turn the current up to your desired setting.

As you can see in this video with this 445 diode 4.6V only let me put in about 900mA. So If I wanted to go higher then I would turn it off, disconnect the diode and repeat the whole process and increasing the voltage say 0.1V each time till I found the right voltage to allow the current I want to give it.


Also this was just a quick test for the diode. I would need a heatsink if I wanted to run it for more than a few seconds.

Last edited by DTR; 03-11-2012 at 05:02 AM.
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Old 03-11-2012, 08:42 AM #4
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Default Re: Driver / no driver

Quote:
Originally Posted by DTR View Post
As you can see in this video with this 445 diode 4.6V only let me put in about 900mA. So If I wanted to go higher then I would turn it off, disconnect the diode and repeat the whole process and increasing the voltage say 0.1V each time till I found the right voltage to allow the current I want to give it.
What's the purpose of turning it off? What dangers would there be to dial up the voltage while the diode is running?

Last edited by ryansoh3; 03-11-2012 at 08:42 AM.
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Old 03-11-2012, 11:19 AM #5
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Default Re: Driver / no driver

Cause there is a capacitor on the output. As you set the output voltage, you are charging the cap. Then if you don't turn it off and short the output you keep it charged and can kill the diode.
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Old 03-12-2012, 05:22 AM #6
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Default Re: Driver / no driver

Excellent, tks guys

Jim
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