Led to replace resistor as diode. Help

Started by 03strat, August 01, 2005, 06:26:58 PM

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03strat

I am replacing D7,D9 diodes on a Bos Os2 pedal with led's for better clipping. It looks like resistors are used as thes diodes. How do I tell which direction to orientate the cathode side of the led?
Thanks
I got da blues!!!

niftydog

QuoteIt looks like resistors are used as thes diodes

huh?

um, the cathode should be in the same place as the cathode on the diodes you're replacing.

The cathode of a LED can be identified by numerous methods, all of which can be simply found by googling, but 'cause I'm bored I've done it for you;

- using the diode check setting on your multimeter

- looking inside the diode will reveal two electrodes, one small, one large - the large piece is normally the cathode.

- the lead attached to the cathode will be shorter and there will be a flat spot on the LED body on the cathode side.
niftydog
Shrimp down the pants!!!
“It also sounded something like the movement of furniture, which He
hadn't even created yet, and He was not so pleased.” God (aka Tony Levin)

03strat

If the led is replacing a resistor, how do I know which end the cathode should be located since resistors can go in either direction. Am I mistaken? I am an extreme novice but greatly appreciate your indulgence and thanks for your previous reply.Led is replacing a resistor. orientation of the led is my confusion.
I got da blues!!!

Peter Snowberg

Welcome to the forum. 8)

I'm guessing this pedal has two diodes which are pointed in opposite directions. If so, you don't need to worry about which side is the cathode.... just make sure that you have one pointed in each direction..

Are the diodes you are describing just the same shape as a resistor?... perhaps with a black epoxy or a reddish glass case and a strip on one side?

Resistors are the ones with the colored bands. You can also get diodes, capacitors, and inductors in similar looking packages. If it had a band on one side and no colored bands, it's a diode.
Eschew paradigm obfuscation

niftydog

I think you may have become a bit confused about diodes. Diodes are about the same shape and size as resistors, but they don't have the coloured bands around them. Be sure that what you are replacing is the right part before continuing.

You may also be confused by markings on the PCB or vague references to part numbers on the schematic. It's possible that you are looking for D7 (diode) but have found it's neighbour R34 (resistor) or something like that.

If you are replacing resistors with diodes, you would have to consult the specific modification instructions that I assume you are following.
niftydog
Shrimp down the pants!!!
“It also sounded something like the movement of furniture, which He
hadn't even created yet, and He was not so pleased.” God (aka Tony Levin)

03strat

Thanks for your help. The resistors are small diodes but very faint markings. A drop of alcohol and I could see the cathode stripe. Led's swapped and working great. Again, thanks for the help.
I got da blues!!!