Hfe testing

[night-B]

I just baught a 100pc pack of germanium ac128 and want to test their hfe.
My cheap Dmm usually oscillates between 60 and 160 for the same tranny in hfe mode.
Any advice on a trustworthy Dmm? Or maybe another method to test the hfe?
Thanks

[slimtriggers]

http://www.geofex.com/article_folders/fuzzface/fffram.htm

There's a schematic for building a rig to test leakage and gain if you scroll down the page a bit.

[night-B]

Thanks! 

[FredGarvin]

Or, you could get the following, if you have the money. I've got one and it's stellar. Great for doing huge batches of transistors.

http://www.peakelec.co.uk/acatalog/jz_dca55.html

[k.rock!]

http://www.amazon.com/Triplett-1101-B-Compact-Backlit-Display/dp/B003YHCFTU/ref=pd_ybh_8?pf_rd_p=280800601&pf_rd_s=center-2&pf_rd_t=1501&pf_rd_i=ybh&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1G0SS6KVNW36W62TVXC5

Or this...it's a DMM with transistor testing capabilities for 30 bucks I'm thinking of getting one myself

-Kaleb

[jimmybjj]

http://www.amazon.com/Triplett-1101-B-Compact-Backlit-Display/dp/B003YHCFTU/ref=pd_ybh_8?pf_rd_p=280800601&pf_rd_s=center-2&pf_rd_t=1501&pf_rd_i=ybh&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1G0SS6KVNW36W62TVXC5

Or this...it's a DMM with transistor testing capabilities for 30 bucks I'm thinking of getting one myself

-Kaleb

" you can just gain select them in a DMM that has a transistor checking range. However, all modern DMM's assume that the transistor being testing has no leakage at all. They just put a metered amount of base current in and look for how much collector current comes out. With germanium's inherently higher leakage, this just makes a leaky device look like a higher gain device."

I would check out the first link in this thread if you want to measure germaniums.

[Fastocker]

Those cheaper DVMs won't normally work with germanium transistors --- I know, I have one.  The upside is you can use them to test LEDs, though.

I also have the Peak Atlast DCA55 and it not only measures hfe and leakage quickly but also IDs the emitter, collector and base no matter how you connect the leads.  If you're going to do a lot of work with transistors it's well worth it.

[bigmufffuzzwizz]

Those cheaper DVMs won't normally work with germanium transistors --- I know, I have one.  The upside is you can use them to test LEDs, though.

I also have the Peak Atlast DCA55 and it not only measures hfe and leakage quickly but also IDs the emitter, collector and base no matter how you connect the leads.  If you're going to do a lot of work with transistors it's well worth it.

OOhh on the wishlist!

[night-B]

+1 I'll buy one soon. I've got a hundred of germs to check so it's worth the price 
Thanks for the link!

[FredGarvin]

The DCA55 shows leakage and gain with germanium devices.

I've several DMM's and the transistor checking is mediocre, sure, geofex's guide to testing leakage work's but tedious if you have a lot to go through.

The DCA55 is the cat's a**!

[gtr2]

Now instead of gassing for pedals, I gas for stuff for pedal building.  Oh it's a cruel tailspin I'm in.

[night-B]

That's right Josh!
+ I'm hunting a stock of ac127 'cause the selling price for one piece makes me sweat.
If I find a good deal I'll test and label them... Then I'll be able to sell matched and tested germs for cheaper than usual, if you guys need some 
My wife is mad each time I receive a package 'cause I own a massive collection of diodes trannies and tubes 

[jimmybjj]

I just baught a 100pc pack of germanium ac128 and want to test their hfe.
My cheap Dmm usually oscillates between 60 and 160 for the same tranny in hfe mode.
Any advice on a trustworthy Dmm? Or maybe another method to test the hfe?
Thanks

If you don't mind where did you buy 100 ac128's? If you do I understand.

[bigmufffuzzwizz]

That's right Josh!
+ I'm hunting a stock of ac127 'cause the selling price for one piece makes me sweat.
If I find a good deal I'll test and label them... Then I'll be able to sell matched and tested germs for cheaper than usual, if you guys need some 
My wife is mad each time I receive a package 'cause I own a massive collection of diodes trannies and tubes 

I'd like to buy some of these if you end up doing this!

[night-B]

A small electronic retailer has closed his shop due to bankrupt. He sold his components for cheap. Unfortunately I didn't owned as much money as I wanted at that moment but I took some mini tube, preamp tubes (5 of each I'll keep for myself), a lot of modern transistors such as BS170, J201... a lot of 2n2222a, a pack of 100 germanium ac128 and his last pack of 10 ac127.
I got the ac128 for approx 0.75$ each and 1.7$ for the ac127.
He told me he has found these old stuff in mass quantity from a german seller on ebay some years ago.
Maybe there's still some good bids on ebay to do.
I think I'll buy the transistor testor from peak next month, and then I'll sell some of the stuff.