typical forward voltage for 1n34a diodes

[tabbycat]

hey all, just a quick question but one i wanted to put to experienced heads here after browsing the webs and not being able to get a firm yes/no consensus.

basically i bought some diodes for clipping. 1n34a.

first batch i bought have a forward voltage of 0.320-0.340, which seems about standard from what i've read elsewhere.
they have clear glass, red wires and a thin green band like these: http://crystalreceiver.co.uk/img/10-005-560.jpg

the second batch i bought have a forward voltage of 0.220-0.240, which seems rather lowish from what i've read elsewhere.
they have clear glass, red wires and a thick black band like these: http://www.mammothelectronics.com/1N34A-p/120-1017.htm

amz, whom we know is a wise owl, seems to suggest they may both be off beam. plot thickens. http://www.muzique.com/news/fake-ge-diodes/

i don't mind so much about the lowish reading ones if they are germanium, as i can use them in any 0.230 setting. but am wondering if that low a reading might suggest they are not germanium, and therefore not ideal for clipping.

they both came from the same source, sold individually for stomp box use?

any thoughts based on your experience?

also, am just getting into clipping and the joys or germanium (just retro-installing a four way germanium diode switch in my first build superfuzz) so am looking for interesting must-try diodes to broaden my clipping palette. ideas welcome?

thanks, tabbycat.

[DrNomis]

hey all, just a quick question but one i wanted to put to experienced heads here after browsing the webs and not being able to get a firm yes/no consensus.

basically i bought some diodes for clipping. 1n34a.

first batch i bought have a forward voltage of 0.320-0.340, which seems about standard from what i've read elsewhere.
they have clear glass, red wires and a thin green band like these: http://crystalreceiver.co.uk/img/10-005-560.jpg

the second batch i bought have a forward voltage of 0.220-0.240, which seems rather lowish from what i've read elsewhere.
they have clear glass, red wires and a thick black band like these: http://www.mammothelectronics.com/1N34A-p/120-1017.htm

amz, whom we know is a wise owl, seems to suggest they may both be off beam. plot thickens. http://www.muzique.com/news/fake-ge-diodes/

i don't mind so much about the lowish reading ones if they are germanium, as i can use them in any 0.230 setting. but am wondering if that low a reading might suggest they are not germanium, and therefore not ideal for clipping.

they both came from the same source, sold individually for stomp box use?

any thoughts based on your experience?

also, am just getting into clipping and the joys or germanium (just retro-installing a four way germanium diode switch in my first build superfuzz) so am looking for interesting must-try diodes to broaden my clipping palette. ideas welcome?

thanks, tabbycat.

It's perfectly normal for Germanium Small-Signal diodes, like the 1N34A, to have a forward-voltage which can measure anywhere from .1V to .3V, I've even come across some that measured .6V too, Germanium is a funny semiconductor material, a Germanium diode doesn't have a well-defined turn-on point like a Silicon diode does,if you have a look at the two screenshots below, the top one shows the clipping you get with Silicon Diodes and the bottom one shows the clipping you get with Germanium Diodes:

[tabbycat]

thanks dr nomis.

they were bought from a usually reliable source. he does make an effort to get the best stuff for stomps in, so i'm pretty certain he wouldn't risk selling tat because he would be aware that his market would pull him up on it. ebayers in china not always so conscientious or careful. though obviously prices reflect that respective attention to detail.

have just tried what i intended to be a heat test. i held the germaniums up to a hot tungsten bulb for about 30 seconds so they warmed up a bit then quickly got the dmm on them. they started at 0.216 and over the course of 30 seconds crept back up to 0.240 as they cooled (which was their original cold reading). not sure how scientific a test this is but it seems to fit with germanuim behaviour, from what i understand.

thanks for the sillyscope images. very retro-futurist. have always wanted to project a giant 10 feet x 10 feet image of one behind me as i play. just like the shapes.

tabbycat.

[DrNomis]

thanks dr nomis.

they were bought from a usually reliable source. he does make an effort to get the best stuff for stomps in, so i'm pretty certain he wouldn't risk selling tat because he would be aware that his market would pull him up on it. ebayers in china not always so conscientious or careful. though obviously prices reflect that respective attention to detail.

have just tried what i intended to be a heat test. i held the germaniums up to a hot tungsten bulb for about 30 seconds so they warmed up a bit then quickly got the dmm on them. they started at 0.216 and over the course of 30 seconds crept back up to 0.240 as they cooled (which was their original cold reading). not sure how scientific a test this is but it seems to fit with germanuim behaviour, from what i understand.

thanks for the sillyscope images. very retro-futurist. have always wanted to project a giant 10 feet x 10 feet image of one behind me as i play. just like the shapes.

tabbycat.

Yep, that diode is displaying typical Germanium temperature-sensitive behaviour, or what I would be expecting.....

[tabbycat]

have just tried what i intended to be a heat test. i held the germaniums up to a hot tungsten bulb for about 30 seconds so they warmed up a bit then quickly got the dmm on them. they started at 0.216 and over the course of 30 seconds crept back up to 0.240 as they cooled (which was their original cold reading). not sure how scientific a test this is but it seems to fit with germanuim behaviour, from what i understand.

Yep, that diode is displaying typical Germanium temperature-sensitive behaviour, or what I would be expecting.....

sweet. thanks for the confirmation, dr nomis. have now got an evenly staged progression across four different pairs of germaniums, from 0.216 to 0.366, on a 4-position diode switch.

how much more dark and brooding could my superfuzz be? the answer is none. none more dark and brooding.

will post pictures as soon as reassembled.

[DrNomis]

have just tried what i intended to be a heat test. i held the germaniums up to a hot tungsten bulb for about 30 seconds so they warmed up a bit then quickly got the dmm on them. they started at 0.216 and over the course of 30 seconds crept back up to 0.240 as they cooled (which was their original cold reading). not sure how scientific a test this is but it seems to fit with germanuim behaviour, from what i understand.

Yep, that diode is displaying typical Germanium temperature-sensitive behaviour, or what I would be expecting.....

sweet. thanks for the confirmation, dr nomis. have now got an evenly staged progression across four different pairs of germaniums, from 0.216 to 0.366, on a 4-position diode switch.

how much more dark and brooding could my superfuzz be? the answer is none. none more dark and brooding.

will post pictures as soon as reassembled.

In a pinch, you can also use Germanium transistors as Diodes, all you need to do is work out which of the leads is the C (Collector), B (Base), and E (Emitter), then trim the C lead short and just wire the B and E leads in as a Diode, for a PNP Germanium transistor the B lead becomes the cathode and the E lead the anode......


The reverse is the case for an NPN Germanium transistor....

[mictester]

In a pinch, you can also use Germanium transistors as Diodes, all you need to do is work out which of the leads is the C (Collector), B (Base), and E (Emitter), then trim the C lead short and just wire the B and E leads in as a Diode, for a PNP Germanium transistor the B lead becomes the cathode and the E lead the anode......
The reverse is the case for an NPN Germanium transistor....

.....That's how I use up the really leaky, nasty germanium transistors I have in the miscellaneous / useless transistor drawer! I use them in germanium clippers.

[tabbycat]

In a pinch, you can also use Germanium transistors as Diodes, all you need to do is work out which of the leads is the C (Collector), B (Base), and E (Emitter), then trim the C lead short and just wire the B and E leads in as a Diode, for a PNP Germanium transistor the B lead becomes the cathode and the E lead the anode......

The reverse is the case for an NPN Germanium transistor....

thanks for the tip, dr nomis. B and E, will remember that. are germanium transistors used as clipping diodes in any way different in responsiveness (is that a word?) to germanium diodes?

(sorry to extend out the suggestion beyond the original question but i've got a busy-head on today, so every idea that enters it generates ten more. have been hanging with bob moog and he's quite an inspiring character. https://www.freestompboxes.org/viewtopic ... 35#p245635 )

[DrNomis]

In a pinch, you can also use Germanium transistors as Diodes, all you need to do is work out which of the leads is the C (Collector), B (Base), and E (Emitter), then trim the C lead short and just wire the B and E leads in as a Diode, for a PNP Germanium transistor the B lead becomes the cathode and the E lead the anode......

The reverse is the case for an NPN Germanium transistor....

thanks for the tip, dr nomis. B and E, will remember that. are germanium transistors used as clipping diodes in any way different in responsiveness (is that a word?) to germanium diodes?

(sorry to extend out the suggestion beyond the original question but i've got a busy-head on today, so every idea that enters it generates ten more. have been hanging with bob moog and he's quite an inspiring character. https://www.freestompboxes.org/viewtopic ... 35#p245635 )

Actually, no, the response is the same as if you used a normal Germanium Diode, you can think of a PNP transistor as two diodes with their cathodes connected together, one diode is formed by the Collector-Base junction, and the other diode is formed by the Emitter-Base junction.....

[tabbycat]

thanks for the tip, dr nomis. B and E, will remember that. are germanium transistors used as clipping diodes in any way different in responsiveness (is that a word?) to germanium diodes?

Actually, no, the response is the same as if you used a normal Germanium Diode, you can think of a PNP transistor as two diodes with their cathodes connected together, one diode is formed by the Collector-Base junction, and the other diode is formed by the Emitter-Base junction.....

thanks again, dr nomis. you are an education.

[electrip]

Well, first i don't recommend cutting of legs of leaky transistors,
there are circuits which need leakage
and other circuits which nullify most of the leakage.
(at least lcbo, lceo can't be prevented).

There are 5 ways to set up a diode configuration with a transistor.
1.Base-Emitter (Standard)
2.Base-Collector (slightly lower Vf than 1.)
3.Base-(Collector||Emitter) (slightly lower Vf than 2.)
4.Emitter-(Base||Collector) (way lower Vf)
5.Collector-(Base||Emitter) (similar to 4.)

Way lower means Vf less than 100mV @1 mA compared to 160-170mV @1mA.
(175mV@12mA vs 290mV@12mA)
Put in a trimmer in front of the collector and you can dial in Vf in that range.

Tested transistor was Siemens-Halske AC153 V
Test Result:
PNP Germanium BJT
Red-C Green-B Blue-E
HFE=54 at Ic=5,02mA
Vbe=0,247V at Ib=5,00mA
IcLeak=0,195mA

electrip