2N3569 in odd package - Page 1
Forum section: electronics / beginners

author: l0rd_hex
author_rank: Regular Contributor
timestamp: February 19, 2016, 09:39:33 pm
content: Hi folks,I came across a project that has some Fairchild 2N3569 transistors in it but I don't see much documentation on the particular package... I think it might be the TO-105 but I'm not sure.I've attached a picture of it.I also tried to figure out which pins are which using the diode setting on my DMM. I get 2.044V between one pin (#1) and the other (#2), 0.715V between the same pin (#1) and another (#3) and 2.898V between #2 and #3. I am measuring this in-circuit however.Does anyone recognize this package and know the pinout?Thanks!

author: nour
author_rank: Frequent Contributor
timestamp: February 19, 2016, 09:45:12 pm
content: how old those components

author: dcel
author_rank: Regular Contributor
timestamp: February 19, 2016, 09:49:24 pm
content: Case is to-39 plastic variant.CrOn edit: i just put 2n number into google with 'case' and found visual match.

author: Paul Price
author_rank: Super Contributor
timestamp: February 19, 2016, 09:50:17 pm
content: Usually the center lead is the base, the tab is the collector. If the center lead is the base you will see <.7V with an ohmmeter to the collector and emitter from the base. If you then hook the transistor up in a common-emitter circuit, emitter grounded, collector to +5V and apply a 100k to +5V to the base, you will find that reversing the collector and emitter will result in one configuration resulting in lower collector current, this is then the reversed connection of C and E. You can use a 1K resistor from the collector to +5.

author: chris_leyson
author_rank: Super Contributor
timestamp: February 19, 2016, 10:08:45 pm
content: Thats old school TO-105. Ceramic lead frame with epoxy encapsulation. Don't see it much but they did LEDs TO-105 style back in the day.

author: Cliff Matthews
author_rank: Unknown
timestamp: February 19, 2016, 10:14:33 pm
content: They're humorously called Glob top's. Collector is left of the flat side, and base is the middle on a 2N3641 I have in stock.

author: chris_leyson
author_rank: Super Contributor
timestamp: February 19, 2016, 10:23:57 pm
content: An amazing piece of metal glass ceramic dare I say valve or tube manufacturing, fucking good gas seal, and the semiconductor guys call them Glob top's. wtf

author: chris_leyson
author_rank: Super Contributor
timestamp: February 19, 2016, 10:50:19 pm
content: Yeah man, keep it, it's semiconductor history. You don't find many glob tops, FETs LEDs Transistors. If I dig really deep I still won't find a glob top be it transistor fet or led.

author: Paul Price
author_rank: Super Contributor
timestamp: February 19, 2016, 10:55:10 pm
content: Having worked on more than a few instruments using this type of transistor cases, I can attest to the chance of these devices failing due to any combination of time and temperature to be quite high. Device reliability is not this case's strong point and that is likely why this device packaging has long-since been abandoned.

author: l0rd_hex
author_rank: Regular Contributor
timestamp: February 20, 2016, 12:12:39 am
content: Wow, what an amazing response! Thank you one and all.For those who are curious this was from a vacuum pump controller I picked out of the electronics scrap pile at my University Chemistry department. There was an external head gauge that was hooked up to a UA741TC op-amp (on the board I showed), along with a potentiometer to set the desired trigger point (when the pumps should switch back on). From what I can tell the opamp switched on the transistor(s) which then switched on a relay which switched on a 30A / 120V mercury reed switch which powered some plugs on the back.The date code on the opamp is from late 77 so I imagine the rest of the components date from there too. I've included some pictures for the curious:

author: timb
author_rank: Super Contributor
timestamp: February 20, 2016, 12:19:40 am
content: I just pulled one of these out of an old Power Designs 2005A I was parting out last night. Never seen one before myself, either. Cute little packages.

author: Paul Price
author_rank: Super Contributor
timestamp: February 20, 2016, 12:22:48 am
content: The obvious question is, does that thing still be able and going to be put to work..or you just wanna whatsa whatsit?

author: l0rd_hex
author_rank: Regular Contributor
timestamp: February 20, 2016, 01:11:04 am
content: This beauty is long retired, I just snagged it from the electronic scrap pile because it looked interesting... plus my ZD-985 vacuum desoldering pump is hunnnnngry,

author: timb
author_rank: Super Contributor
timestamp: February 20, 2016, 01:27:18 pm
content: Quote from: timb on February 20, 2016, 12:19:40 amTook some closeup photos to share with the class. You can really see the "Glop Top" on the ceramic base in detail!