Is there a way to know the specs of an LED if you've lost the packaging, etc.?
I comissioned someone to build a circuit for my 1/350 Refit, and he did an outstanding job. However, a few LEDs are not lighting, which could be a few things (but not the board). I need to get new LEDs, but do not know what the power/volts/amps/etc. are. The guy who built the circuit forgot himself, as it has been awhile. Am I safe just ordering 3mm Ultrabright LEDs and running with it (the originals are 3mm Ultrabrights)?
Is the worse that can happen a burn out?
Thanks, and I hope this post isn't too confusing or otherwise silly.
Determining LED specs only by examining LED
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Sparky
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The worst that will happen is the LED life will be shorter than expected. I.E. you put it all in and they die after a year.
You're best bet is to find a standard LED with the highest current and voltage rating.
Also you can hook up an LED and test the circuit. Read the voltage that is actually being delievered to the LED (you need the LED there for proper load in some circutis so its best to put it in there). You can also clip a current meter in line and read the current going into the LED while the circuit is running. This means that you don't solder one side of the LED into the circuit. Most voltage meters have a current meter setting, for very low currents, like an LED, these read by being in line/series/daisy chained while the circuit is running.
You're best bet is to find a standard LED with the highest current and voltage rating.
Also you can hook up an LED and test the circuit. Read the voltage that is actually being delievered to the LED (you need the LED there for proper load in some circutis so its best to put it in there). You can also clip a current meter in line and read the current going into the LED while the circuit is running. This means that you don't solder one side of the LED into the circuit. Most voltage meters have a current meter setting, for very low currents, like an LED, these read by being in line/series/daisy chained while the circuit is running.
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jwrjr
If you assume that the leds are rated at 25ma, you will not damage anything. A few are rated for higher current, but not all that many. The forward voltage for a led depends on the color - blue and white are rated at 3.5 volts, all other visible colors are rated at 1.75 volts. If you replace a led with a similar one (need not be exact) nothing bad should happen. If it doesn't light, check: a.it isn't in backwards and b. the resistor isn't damaged.