Need help understanding the datasheet for a 70 year old M1752 Transistor - Page 1
Forum section: electronics / projects

author: RonFred2
author_rank: Contributor
timestamp: March 22, 2021, 07:51:01 am
content: I have one of the limited supply of the first grown-junction transistors called the M1752. This germanium part was sent to some 200 labs as a prototype to see what changes would be needed to make commercial grade junction transistors.The packing envelope (I am calling it the datasheet) has several values:Alpha: .9927Rc: 6.2Rb: 5,000Re: 13.0Ico: 0.7 uAZe: 8 VZC 80 VI understand the "Alpha" but I wonder what the remaining resistance, current and Z values mean?For example is this some short hand for a bench circuit setup with resistance and voltage / current? If so anyone know what that circuit might look like?I am attaching my test results for this part using a Peak DCA Pro. But I am thinking that the test values by default may be wrong. I can adjust the range and step values for curve traces but having the envelop values is not enough for me.

author: Dunckx
author_rank: Contributor
timestamp: March 22, 2021, 10:15:17 am
content: Have a look at the Internet Archive's collection of early transistor papers:https://archive.org/search.php?query=%28transistor%29%20AND%20date%3A%5B1948-01-01%20TO%201960-01-01%5DThere's several examples from the BSTJ such as:https://archive.org/details/bstj31-3-411/page/n27/mode/2uppublished 1952 which even mentions the M1752.https://archive.org/details/bstj35-1-1/page/n5/mode/2upwhich describes early work (1956) on the junction transistor.There are lumped circuits in the latter showing various values of equivalent resistance and maybe the parameters on the envelope you have are connected. Just a guess.See alsohttps://archive.org/details/transistoramplif00bauewhich could be of interest, it's a 1957 study on transistor amplifiers. The R values could be input resistance with output AC open or shorted, or output resistance with input AC open or shorted. I think if you want an interpretation of those numbers on the envelope, the early days of transistor research are the most likely to yield relevant answers.My 2p worth.

author: magic
author_rank: Super Contributor
timestamp: March 22, 2021, 11:38:28 am
content: The last two could be breakdown ratings, and not sure if the big Z is part of that.

author: RonFred2
author_rank: Contributor
timestamp: March 23, 2021, 06:32:53 am
content: Thank you Dunckx:I also found this doc on archive.orgThis one is all about the M1752: "Properties of junction transistors"https://ia801602.us.archive.org/22/items/Q00016/Q00016.pdfI am going to study the references you have suggested.

author: cheater
author_rank: Regular Contributor
timestamp: March 23, 2021, 04:08:43 pm
content: I wonder how you came about this transistor? That's a very cool find!

author: RonFred2
author_rank: Contributor
timestamp: March 23, 2021, 08:16:40 pm
content: I bought my M1752 (M-1752) on ebay from the Southwest Museum of Engineering,Communications and Computation: smecc.orgThey have a few more of these M1752 for sale on ebay along with other parts.The smecc.org is looking for funds to update their building post-COVID as I understand it.