Transistor tester - Page 1
Forum section: electronics / rf-microwave

author: scorponog
author_rank: Newbie
timestamp: April 27, 2024, 04:25:38 am
content: Howdy!Can anyone recommend a transistor tester that would work for germanium transistor's?I was looking at the DCA-75 but those seem to be out of stock everywhere. I have a multi unit that does a limited amount of testing now but would like to get a better unit.TIA

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: April 27, 2024, 08:28:55 am
content: The DCA-75 is a very nice unit. One of the Peak USA distributors has the DCA-75 in stock,http://www.alltronics.com/I have the more basic DCA-55 which is currently in stock at Digikey.SJ

author: Calambres
author_rank: Frequent Contributor
timestamp: April 27, 2024, 06:27:09 pm
content: Ditto.Those chinese testers work so-so with Ge trannies.I've got a DCA-55 and it works pretty well with these components.

author: madires
author_rank: Super Contributor
timestamp: April 27, 2024, 07:18:49 pm
content: Quote from: Calambres on April 27, 2024, 06:27:09 pmTheir firmware is based on an older version of the OSHW k-firmware with issues discerning Ge BJTs from JFETs. If you have a tester with a genuine ATmega you could flash the m-firmware which comes with a few additional checks to tell Ge BJTs and JFETs apart.

author: coppercone2
author_rank: Super Contributor
timestamp: April 27, 2024, 11:15:07 pm
content: you should try this in the repair forum since a germanium transistor is a device present in much more stuff then radios. the audio people know, and people are VERY concerned about their germanium transistors

author: Calambres
author_rank: Frequent Contributor
timestamp: April 28, 2024, 06:48:12 am
content: Quote from: madires on April 27, 2024, 07:18:49 pmI have some of those units, even a couple with genuine ATmega processor (AY-AT) and have never experienced a Ge trannie being identified as a JFET. On the other hand, the measurements are off, always reading high beta and leakage.I have not investigated the reflashing method. It seems to me a bit cumbersome from what I've seen. Is there a "dummies guide" to do it easily?

author: madires
author_rank: Super Contributor
timestamp: April 28, 2024, 08:42:40 am
content: For example:-https://github.com/carl1961/Transistor-Tester-AVR-Compiled-files-On-Windowsor-

author: Calambres
author_rank: Frequent Contributor
timestamp: April 28, 2024, 03:54:39 pm
content: Wow!... lots of reading

author: graybeard
author_rank: Frequent Contributor
timestamp: April 28, 2024, 10:24:23 pm
content: My $10 Chinese tester is doing an acceptable job on Ge BJTs and diodes. I have had these parts in my collection since I was in Jr. High school.

author: max-bit
author_rank: Frequent Contributor
timestamp: April 29, 2024, 06:18:23 am
content: But I am surprised that so far no one has developed a "cheap" tester of TRANSISTORS, diodes, thyristors, thraics, with capabilities slightly beyond the "battery" values, so that Uce ~ 100V Ic ~ 1A etc.It is even very difficult to find (if there are any) such devices from larger companies (but not costing xx k$)Something in the range of a few hundred dollars to ~$1000These "toys" have been on the market for many years for prices ranging from several dollars - a dozen or so dollars.

author: madires
author_rank: Super Contributor
timestamp: April 29, 2024, 09:43:18 am
content: Quote from: Calambres on April 28, 2024, 06:48:12 amIt's not a major issue and can happen when the BJT's leakage current exceeds some threshold. Or if a JFET has a very low I_DSS. If you don't use such transistors it's possible that you'll never encounter that issue.

author: Calambres
author_rank: Frequent Contributor
timestamp: April 30, 2024, 05:54:31 am
content: Well, as a matter of fact, I usea lotof Ge trannies and many JFETs too. My hobby is making guitar effects pedals and those two components are essential for thatThat said, I tend to use the Peak Atlas DCA-55 the most for the aforementioned reasons (see third post in this thread).