how to match devices -help-

Stefanoo · 2nd January 2007, 01:49 PM

I'm searching on the forum how to match transistor-jfet-mosfet.

I would like to know...if it is possible do it on your own.
If so, is there any circuit test that i can build and that work fine for the purpose?

hope to receive ...as everytime...your good advice!

best regards,
Stefano.

moe29 · 2nd January 2007, 02:50 PM

which FETS are you trying to match?

is there a particular amp you are going to build?

Check out www.passdiy.com and under the Articles section there is a paper on matching FETS.

Stefanoo · 2nd January 2007, 03:08 PM

well actually i have to repair my electrocompaniet ECI-4 and i have to replace the transistor (driver and output stage).
Since the configuration is in differential i would like to replace...since i'm have to....with complementary matched type.

The devices that i have to match are BJT (motorola MJL3281A and 1302A and Toshiba 2sa1350y and 2sc3421y).....which i still have to find somewhere...and i hope somebody could help me.

I also found them on the phoenix-components.com...but they since to supply only the industries.

x84andrea · 2nd January 2007, 03:33 PM

ciao, parliamo in italiano! basta che gli mandi una corrente fissa e calcoli la differenza di potenziale con il mos collegato a diodo,
puoi usare un lm317 in modalita sorgente di corrente e fare le misurazioni, mandagli 500ma o più!
per fare questo devi dissipare il317 e il mos, se vuoi altro fammi sapere a x84andrea@libero.it

carpenter · 2nd January 2007, 03:33 PM

If you're talking about basic VGS matching, I saw suggestions in Nelson's DIY op amp article. I have a drawing if you want it.

GRollins · 2nd January 2007, 03:51 PM

Since they're bipolars, Vgs isn't applicable, unfortunately. That's for FETs. The equivalent measurement for bipolars--Vbe--is quite consistent.
What parameter needs to be matched? Beta? If so, to what spec?

Grey

carpenter · 2nd January 2007, 05:15 PM

Quote:

I'm searching on the forum how to match transistor-jfet-mosfet.

I guess this kind of threw me.

DIY op amps also shows how to match bipolars.

Stefanoo · 3rd January 2007, 06:39 AM

thanks guys for the posts.
I would like to have a little circuit test for matching Bipolar Transistor (mostly) and also have a circuit ...that i guess it's different... for MOS and FET.

I mean.....what do the companies use for selecting their componens? does anybody know it?

2nd January 2007, 01:49 PM	#1
Stefanoo diyAudio Member Join Date: Apr 2006 Location: italia - ora USA -WI	how to match devices -help- I'm searching on the forum how to match transistor-jfet-mosfet. I would like to know...if it is possible do it on your own. If so, is there any circuit test that i can build and that work fine for the purpose? hope to receive ...as everytime...your good advice! best regards, Stefano. __________________ Stefano

2nd January 2007, 03:08 PM	#3
Stefanoo diyAudio Member Join Date: Apr 2006 Location: italia - ora USA -WI	well actually i have to repair my electrocompaniet ECI-4 and i have to replace the transistor (driver and output stage). Since the configuration is in differential i would like to replace...since i'm have to....with complementary matched type. The devices that i have to match are BJT (motorola MJL3281A and 1302A and Toshiba 2sa1350y and 2sc3421y).....which i still have to find somewhere...and i hope somebody could help me. I also found them on the phoenix-components.com...but they since to supply only the industries. __________________ Stefano

2nd January 2007, 03:33 PM	#5
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	If you're talking about basic VGS matching, I saw suggestions in Nelson's DIY op amp article. I have a drawing if you want it. __________________ I enjoy audio so much that I constructed a web site. I share my ideas at: www.inlowsound.com

3rd January 2007, 06:39 AM	#8
Stefanoo diyAudio Member Join Date: Apr 2006 Location: italia - ora USA -WI	thanks guys for the posts. I would like to have a little circuit test for matching Bipolar Transistor (mostly) and also have a circuit ...that i guess it's different... for MOS and FET. I mean.....what do the companies use for selecting their componens? does anybody know it? __________________ Stefano

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2nd January 2007, 02:50 PM	#2
moe29 diyAudio Member Join Date: Dec 2002 Location: Florida	which FETS are you trying to match? is there a particular amp you are going to build? Check out www.passdiy.com and under the Articles section there is a paper on matching FETS.

2nd January 2007, 03:33 PM	#4
x84andrea diyAudio Member Join Date: Jan 2005 Location: Roma	ciao, parliamo in italiano! basta che gli mandi una corrente fissa e calcoli la differenza di potenziale con il mos collegato a diodo, puoi usare un lm317 in modalita sorgente di corrente e fare le misurazioni, mandagli 500ma o più! per fare questo devi dissipare il317 e il mos, se vuoi altro fammi sapere a x84andrea@libero.it

2nd January 2007, 03:51 PM	#6
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Since they're bipolars, Vgs isn't applicable, unfortunately. That's for FETs. The equivalent measurement for bipolars--Vbe--is quite consistent. What parameter needs to be matched? Beta? If so, to what spec? Grey

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