BIP 26x-x 047? and glass diodes that aren't diodes? What are these old parts? - Page 1
Forum section: electronics / beginners

author: dentaku
author_rank: Frequent Contributor
timestamp: August 20, 2013, 03:05:47 pm
content: I was cleaning one of those plastic cabinets of little drawers I got along with a bunch of stuff I bought from the collection of an old man why died recently and found these two little glass "things" with what looks like copper leads.They're not diodes according to my multimeter but I have no clue what they are.Also, I found these mixed in with a bunch of 74xx stuff and SIL40xx stuff.They're all BIP 261x-x 047 and it looks like one is 027.I can't find what they are.

author: Stonent
author_rank: Super Contributor
timestamp: August 20, 2013, 03:19:17 pm
content: Well, what does your multimeter say?If they're less than an ohm, probably a fuse. More than a ohm, probably a resistor.The chips are decade counters for driving Nixie Tubes.http://www.wps.com/archives/tube-datasheets/Datasheets/Burroughs-1061K/10.JPG

author: c4757p
author_rank: Super Contributor
timestamp: August 20, 2013, 03:21:21 pm
content: Bidirectional TVS diodes?

author: Paul Price
author_rank: Super Contributor
timestamp: August 20, 2013, 03:53:07 pm
content: Charge one or more large value capacitors from AC line voltage to peak DC voltage. Remove charged caps and put them in series and connect to a 10K resistor to the "diode" DUT with your scope attached in parallel via a DIY aprox. 10/1 attenuator (i.e. 100k/10K) to a 10x scope probe input on 5V to 10/div DC range. You will see the what this device is, probably a fixed protective breakdown voltage didoe, then switch capacitor polarity and repeat measurement.

author: c4757p
author_rank: Super Contributor
timestamp: August 20, 2013, 04:03:48 pm
content: Quote from: Paul Price on August 20, 2013, 03:53:07 pmFTFYYes, it should be obvious, but you shouldn't assume it won't get missed in a moment of cerebral flatulence.

author: free_electron
author_rank: Super Contributor
timestamp: August 20, 2013, 05:07:11 pm
content: Those glass things are Diacs. they are a bidirectional avalanche diode that triggers at about 40 volts. used to ignite Thyristors (SCR's) and Triacs.

author: dentaku
author_rank: Frequent Contributor
timestamp: August 20, 2013, 11:08:01 pm
content: OK, that explains why the diode test on my multimeter reads .OL both ways.Quote from: free_electron on August 20, 2013, 05:07:11 pm

author: dentaku
author_rank: Frequent Contributor
timestamp: August 20, 2013, 11:18:12 pm
content: Quote from: Stonent on August 20, 2013, 03:19:17 pmWow, that's some old stuffI DID find a NIXIE tube mixed in with all the other stuff too so it's logical that I also have the drivers for them. I also have some of those old LEDs with the round bubble like lenses over them.

author: Stonent
author_rank: Super Contributor
timestamp: August 22, 2013, 02:18:09 am
content: I find it interesting the haphazard way they stamped the chips. Nothing is lined up.

author: dentaku
author_rank: Frequent Contributor
timestamp: August 22, 2013, 02:23:52 pm
content: I'm lucky some of them weren't missing half of the text considering how misaligned it is.Quote from: Stonent on August 22, 2013, 02:18:09 am