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Re: FET help, please

:

6/4/1999 8:07 PM

Re: FET help, please

>It's not all that easy to measure JFET gain without a circuit to test it in.
Common digital multimeters have transistor gain testers built in, but not
JFET gain testers.

I'm from the ICE680R era (a fine multimeter I bought in the early 70's) is the one I use. No transistor measurements I'm afraid. Although, as you can appreciate, I only use it for basic things and measurements like now, building effects.

>The easiest tester is to build a simple gain circuit and listen to several through
the circuit.

I'll try to find one. Is there an efect that has a simple gain stage wich I could build. Something like: from cap xx to cap xxx...

>The vox treble booster is not designed for a germanium device, and would
probably have very low output with a germanium, unless it's some variation
of the VTB I've not seen - which is always possible.

I think it's the original. I tried an old AC175 and I liked the sound a lot, but the output was very low. I then put a BC548: much more output, but I didn't like the sound. So, "off the box and in to a plastic bag" it went

I'm not quite sure, but to me, I think that some germanium transistors give a smoother sound.

6/3/1999 10:34 PM
aron	I'm confused. Does the Vox use a FET? Or are you just asking about how to measure a FET? For germaniums and other transistors, use a multimeter that can measure the hFE of the transistor. I recommend a very good multimeter on my web site in the common questions section. Aron

6/4/1999 8:12 PM

>I'm confused. Does the Vox use a FET? Or are you just asking about how to
measure a FET?

It was my fault, Aron. I was asking two somilar questions all mixed up.

>For germaniums and other transistors, use a multimeter that can measure the
hFE of the transistor.

Thank you very much for the info, again.
I didn't knew that.

>I recommend a very good multimeter on my web site in the common
questions section.

I'll go to your site (again) and have a look.

JonhC

6/5/1999 12:47 AM
aron	John, Here is the URL just in case: http://www.geocities.com/BourbonStreet/Delta/2133/stompbox/pitfalls.html

6/5/1999 12:50 AM

The Radio Shack model I mention does hFE for measuring gain of transistors, auto pinout identification, PNP vs NPN auto ID, is true RMS (more accurate???), measures capacitors, tests diodes, temperature and best of all,
is auto-ranging (no irritating knob to dial up all the time for ranges). You can also turn off the auto-ranging and go manual.

There are sockets for testing diodes, caps, resistors and transistors which using leads.

It's the best I have found for less than $100. In fact, once it was on sale for $69.95 and then you could get $15 off for joining sprint!!!!

Aron

6/5/1999 7:43 AM

>hFE for measuring gain of
transistors, auto pinout identification, PNP vs NPN auto ID,
...measures capacitors, tests diodes, temperature and best
of all,
is auto-ranging...

>There are sockets for testing diodes, caps, resistors and transistors which
using leads.

Sounds too good to be true.
I'll try to find one of those. Maybe they at RS could even send one overseas...

Thanks a lot! indeed!

JohnC

6/5/1999 9:27 AM
marrk	I have this meter, and love it. It is now on sale for $69.99. Mark

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