Measuring transistors hFE

[Clutz]

Hello all,

I am trying to measure some transistors hFE. According to tangent's website:

Quote:

If you want to match the buffer driver transistors with an hFE meter, the pinout of the transistors are EBC with the pins downward and looking at the flat face of the transistor.

.

So I am trying to measure the hFE of the 2N5486 suggested for use in the PPA2 buffer section. I have placed the transistor into the HFE meter plug of my DMM with the E pin, in the E hole, the B bin in the B hole, and the C pin in the C hole. When I do this - the read out on my meter gives me a . However if I try to place the transistor (i have way more than I need, so I was playing with it", so that the E goes into E, the B goes into C, and the C goes into B, then I get a read out- but I don't know how to make sense of it. (I should add that I am plugging these into the NPN half of the tester)

What should a "typical" read out be for the hFE of the 2N5486 transistors?

Or alternately, anyone have any idea what I'm doing wrong?

 

[amb]

Clutz, the 2N5486 is a JFET (junction field effect transistor), not a BJT (bipolar junction transistor). Hfe is a parameter that applies only to BJTs. You should not attempt to measure a JFET using the Hfe function on a DMM.

 

[Clutz]

Quote:

Originally Posted by amb Clutz, the 2N5486 is a JFET (junction field effect transistor), not a BJT (bipolar junction transistor). Hfe is a parameter that applies only to BJTs. You should not attempt to measure a JFET using the Hfe function on a DMM.

Well.. then I guess that would explain my confusion.

Is there anyway to match JFET transistors? I'd be willing to breadboard something

Thanks again amb,
Clutz

 

[SnoopyRocks]

Quote:

Originally Posted by Clutz Well.. then I guess that would explain my confusion. Is there anyway to match JFET transistors? I'd be willing to breadboard something Thanks again amb, Clutz

http://tangentsoft.net/audio/opamp-bias.html

Scroll down to the bottom of the page.

 

[tangent]

Quote:

Originally Posted by Clutz Is there anyway to match JFET transistors?

There's not much point in PPAv2. R9 and R12 are there to allow you to adjust the various bias points with enough range to cover any reasonable JFET Idss value.

 

[Clutz]

Quote:

Originally Posted by tangent There's not much point in PPAv2. R9 and R12 are there to allow you to adjust the various bias points with enough range to cover any reasonable JFET Idss value.

Thanks as always Snoopy and tangent.