Values

[Brian]

Anybody know the easiest way to measure the value of a diode?

[Saber]

If you mean the forward voltage, the easiest method would be to use a multimeter that has the diode checking function. The reading it gives is the forward voltage (on mine anyway).

If you don't have such a meter, you can simulate this by passing around 1mA through the diode and measuring the voltage across the diode. I don't know how well equipped you are so the simplest way to do this is to put your diode in series with an 8.2k (approximate and not critical value) resistor. Apply 9v (battery if you don't have a power supply) across the series circuit and measure the voltage across the diode. Is that what you're looking for?

[Jehle]

I just got a cheap digital voltmeter with the diode checking function at Radio Shack. I think it was like 20 bucks.

I'll check a few diodes that I have and Brian's Playdoh diodes to see what it tells me. Stay tuned...

[Jehle]

Did a little measuring at home. Here's a few values that I came up with. All numbers in Volts.

I tried all 3 of the Brian Playdoh gizmos.

playdoh 1 0.543

playdoh 2 in parallel 0.512

playdoh 3 in parallel 0.491

Then a few diodes in my junk box

radio shack cheapo 0.542

power diode 0.542

And a few LED's (extra brownie points if you can calculate Planck's constant from these values. )

red led 1.497

orange led 1.457

yellow led 1.703

green led 1.752

And just for grins a transitor or two (using only one pair of the contacts to "fake" a diode).

trasistor1 0.637

trasistor2 0.611

And then I double checked the humbucker in Bloo Dood (> 10.6 k ohms).

0.350 V ac. (pick or strum)

0.085 V ac. (sustaining a note)

Hope this information helps out there Brian. With a good hand full of diodes you could probably get closer. Maybe that's why the black ice is so big. :?

[Saber]

Maybe that's why the black ice is so big. :?

Or maybe the black ice contains a small transformer like I explained in this post:

http://projectguitar.ibforums.com/index.ph...opic=2032&st=15

[Brian]

Nope it doesn't, it's a pair of small diodes that are wrapped together in oppisite directions so either way you wire it up the connection will flow.

I just have the value wrong on the test sample's I sent out so I need to buy another one and measure it again since the first one ended up destroyed, thing about it is they are so simple to make to begin with and I already have a new set of molds .

[KeithHowell]

Bill

Are you sure the calibration on your meter is OK? A silicon diode should have a forward voltage drop of around 0.7v and a germanium around 0.3v

Keith

[Jehle]

Bill

Are you sure the calibration on your meter is OK? A silicon diode should have a forward voltage drop of around 0.7v and a germanium around 0.3v

Keith

This is a cheap meter with no callibration at all.

I know that silicon should measure on average around 0.7, but I just grabbed these out of the junk box and tested at random. I did test a few more diodes that came in at a more expected 0.7xx and a another at ~0.8xx. So, on average the 0.7 measurement is going to hold true. I guess these low values were just a few wild cards.

I was more surprised by the measurement of the orange diode. It should have measured somewhere between red and green, but it was the lowest of all. Strange.