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DIY Stompboxes => Building your own stompbox => Topic started by: midwayfair on September 06, 2012, 01:41:06 PM

Title: Looking for specific diode clipping range: .45 (and .9)
Post by: midwayfair on September 06, 2012, 01:41:06 PM
Is there anything that clips in the .45v range? Everything I could ever want between ~.51 (Mosfets) to .7, and all the diodes I could want at .2 to .4. All the LEDs I could want <1v.

I can build a %^&*tail that hits .45, but I'm just surprised that I've never encountered anything in that specific range during my travels.
Title: Re: Looking for specific diode clipping range: .45 (and .9)
Post by: slacker on September 06, 2012, 01:49:30 PM
Have a look at some Schottky diodes BAT42 and BAT43 are in that sort of range.
Title: Re: Looking for specific diode clipping range: .45 (and .9)
Post by: midwayfair on September 06, 2012, 02:10:28 PM
Quote from: slacker on September 06, 2012, 01:49:30 PM
Have a look at some Schottky diodes BAT42 and BAT43 are in that sort of range.

Thanks!
Title: Re: Looking for specific diode clipping range: .45 (and .9)
Post by: Mark Hammer on September 06, 2012, 02:18:22 PM
There is a fair degree of variation in actual forward voltages of diodes, even within the same category and part number.  I find 1N34 Ge types that measure 190mv and 320mv, and 1N4148 that measure under 500mv up to 650mv.  Ensuring that you hit a specific voltage drop requires you to do one of two things (or both):

a) measure the forward voltage of all the diodes you have, and
b) use combinations of Ge and/or Schottky diodes to add up to the desired value.
Title: Re: Looking for specific diode clipping range: .45 (and .9)
Post by: midwayfair on September 06, 2012, 02:22:43 PM
Quote from: Mark Hammer on September 06, 2012, 02:18:22 PM
There is a fair degree of variation in actual forward voltages of diodes, even within the same category and part number.  I find 1N34 Ge types that measure 190mv and 320mv, and 1N4148 that measure under 500mv up to 650mv.  Ensuring that you hit a specific voltage drop requires you to do one of two things (or both):

a) measure the forward voltage of all the diodes you have, and
b) use combinations of Ge and/or Schottky diodes to add up to the desired value.

Yeah, I have a TON of diodes at the house and I regularly measure them when looking for a specific Fv. But I was really hoping for something that is manufactured with these as target or at least very likely ranges. I have found a few "bad" Germaniums that go all the way up to 1.1v and sometimes find good ones around .37. I had one 4.5v 1N34A but broke it breadboarding. (Doh. :()
Title: Re: Looking for specific diode clipping range: .45 (and .9)
Post by: Pyr0 on September 06, 2012, 05:25:25 PM
I haven't found anything in the 0.45 range, but 2 x 1N5818/1N5187 in series should get pretty close to that, or a combination of many other schotky diodes.

As for the 0.9 v range, I have a load of BA243 with a Vf of ~ 0.95 and also  BAS33 with Vf of ~ 0.92 to 0.95, these are readily available on ebay from minifux1 for a reasonable price but by the 100.
Title: Re: Looking for specific diode clipping range: .45 (and .9)
Post by: Paul Marossy on September 06, 2012, 06:13:51 PM
Would resistors in series alter what voltage they clip at? If so, I suppose it could mess up the frequency response, right?