LED FAQ

Frequent question abouts LED and other types of diodes.
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bradb
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Post by bradb »

Hey guys,

Do any LED's exist out there that have a 9V forward voltage?

anyone have a mouser part number?

should I just forget it and do the resistor in series?

thanks

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modman
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Post by modman »

Hi

I'm not so sure about what your trying to do, there might be other ways to achieve what you're aiming at.

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soulsonic
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Post by soulsonic »

Yes, the resistor is important in any case regardless of the specific voltage of the LED. It provides necessary current-limiting as well as giving the proper voltage.

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bajaman
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Post by bajaman »

some leds are high bright and therefore consume less current = longer battery life.
A 22k resistor in series will still give usable intensity - reduce gradually to 1k for brighter or less efficient leds BUT do not go any lower - the Led will be toast :cry: . I use 4k7 to 10k depending on the application and colour, efficiency etc.
cheers
bajaman

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KHELSTROM
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Post by KHELSTROM »

I'm interested in building the AD3208 analog delay at general guitar gadgets and am wondering if it would be possible to make an LED blink in time with the delay time?

Thanks'

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Post by analogguru »

General Guitar Gadgets - The DIY Stompbox Authority
You should ask the (self-proclaimed) "Authority" first....

But you can try this:

Connect the input of a CD 4040 to pin 2 or 4 of the MN 3102.
At one of the outputs of the divider chain should be a slow pulse rate - visible. connect a low-current-led in series with a resistor 1k - 4k7 to that output. voila...

analogguru
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KHELSTROM
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Post by KHELSTROM »

Thanks analogguru! Now would it be possible to wire it for 3PDT true bypass but still have the repeats trail off after bypassed.

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Sock Puppet
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Post by Sock Puppet »

When I first saw this I thought about an edge triggered monostable from the divider to "blink" the L.E.D. instead of a 50% duty cycle.

Then I looked at the build information and saw that the maximum delay is only 205mS - I had to wonder if a Flashing L.E.D. at 5Hz or faster would be of any use to you at all.

If the delay was in the 1/2 second plus range, I could see how this would be useful.

Just musing,

S.

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Post by Dirk_Hendrik »

KHELSTROM wrote:Now would it be possible to wire it for 3PDT true bypass but still have the repeats trail off after bypassed.
No.

The fact that you want to make it true bypass also states that the trailing is not possible anymore by the definition of what true bypass is.
Sorry. Plain out of planes.

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