HFE Tester circuit for NPN Transistors

[chptunes]

I was reading this article about testing PNP Transistors for Fuzz Face circuits.  http://www.geofex.com/Article_Folders/ffselect.htm

I have a stash of 1590A boxes, and I'd like to use one for this circuit.  Also, I'd like to build a NPN version.  I need verification that I've drawn this alternate version correctly, please..



Thanks,

-Corey

[PRR]

Reverse the probes. (Or ignore the "-" sign on your DMM.)

[chptunes]

Reverse the probes. (Or ignore the "-" sign on your DMM.)

Thanks PRR.  I've updated my plans..



-Corey

[PRR]

A matter of taste:

Since the DMM is right there, I'm not sure what the LED adds except battery drain. If you doubt your battery, poke it with the DMM.

The power switch..... with no LED, and no transistor in the socket, there is NO power drain. As long as you take the transistor out, a power switch is not really needed.

But that's all up to the constructor's taste and intent.

[chptunes]

A matter of taste:

The power switch..... with no LED, and no transistor in the socket, there is NO power drain. As long as you take the transistor out, a power switch is not really needed.

But that's all up to the constructor's taste and intent.

Great thoughts.. Thank you.

[mac]

in my gallery you can find a HTML file you can use to calculate gain and leakage. Just type your measurements and the script does the maths. It is also scalable to obtain gain under different values of base current.

mac

[chptunes]

Thanks mac.. cool resource.

-Corey

[chptunes]

No freakin' way!!  The first 10k and 3.3k Resistors that I pulled from my bin have the followong measured resistances:

3.287k & 9.98k

According to the calculation, their paralleled resistance should equal 2.4726k.  Party!

Online Calc:  http://www.1728.org/resistrs.htm

-Corey

[TTFBuilder]

So... Where's that html hfe calculator?

[mac]

So... Where's that html hfe calculator?

http://www.aronnelson.com/gallery/main.php/v/mac/apps/

mac

[Kipper4]

Thanks Mac.
Saved.

[mac]

Rich,
There is a missing image, similar to the ones above.
I should pack the html page and the picture in a file.
Meanwhile you can download one of the images and edit the html page in any text editor to call the new picture.

mac

[TTFBuilder]

So... Where's that html hfe calculator?

http://www.aronnelson.com/gallery/main.php/v/mac/apps/

mac

Thanks!