I just finished a couple of Cigar Box amps. Everything went well until I soldered the LED leads. I bought 2 prewired kits from Gitty. I checked the the leads with an ohm meter and had good continuity from the circuit board to the ends of the lead. Neither one of the LED's lit up when I turned on the switch. The amps both work well although not to loud. I can't figure out why the LED's don't lite. Take a look at the picks. Any help would be great
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Just as an added note, though they are cheap you can salvage LEDs out of old junk appliances and save some change.
A lot of LED's have a flat spot next to one leg. That's the Cathode. I could never remember what that meant until somebody pointed out that Cat's are negative... So Flat spot to ground.
John
Cool Amp!
Usually you need a resistor before the LED to drop the voltage, you may have over powered it and smoked it. You'll want to look at the specs for your LED but the ones I use get a 330Ohm resistor.
You can also tell the +ve lead by the short tang inside the globe.
Sorry the resistor is to limit current not voltage(knew I had that wrong as soon as I posted it). Size your resistor here
you had it right: depending on the the LED type, it will operate at a voltage drop of anywhere from 1.7v for dim red LEDs to 4.5v for bright white LEDs (check your spec sheet) and you need the resistor to drop the rest of the voltage (wired in series) or else you get a wonderful one-shot flashbulb-LED and then all the magic smoke will leak out.
diodes only conduct one way. chances are you fried them if you hooked them up backwards. the notch should be the positive (+) side.
I didn't see a notch and it probably wouldn't have meant anything to me any way. Live and learn but thanks for the response. I'm all squared away now and the new LED's are working fine, and so are my CBG amps
Looking damn good too! Love those speaker covers!
I may be wrong but I seem to remember when building shifts lights for my track car the LED has one leg longer than the other so maybe if you change the wiring round , does it tell you which way round the wire the LED ?
both leads to the LED was the same but I did change them around and when I put together the 1st amp and the LED didn't work I used the one from the other kit and it didn't work either. Whats the chances that I got 2 bad LED lights. I checked the connections to the amp circuit board and the leads are in the right place according to the diagram supplied with the kit. I used one of these kits about a year ago without any trouble.
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