Anyone know what this is?

[digi2t]

Asking for a friend. So far my internet travels have come up dry. B-498 yields nada. The A25 prefix points me towards aviation parts, but no match yet on the whole part number. Thought I'd give the old timers around here a crack...









My initial thought is a diode bridge. My friend isn't near a DMM right now, so we'll take educated guesses in the meantime.

[Govmnt_Lacky]

I really, really hate that I cannot see pictures posted on here while at work 

[Ice-9]

Wow, it is a hard one to find and I can say I haven't found it in Texas Instruments searches... My first thought was an Optocoupler But my final guess is that its a full wave bridge rectifier.

[Mark Hammer]

My initial thought is a diode bridge. My friend isn't near a DMM right now, so we'll take educated guesses in the meantime.

\
Before I scrolled down to read this part of your post, my first thought was "Hmm, 4 legs, probably a diode bridge".

I'm hoping that we're in the great-minds-think-alike club, and not the fools-seldom-differ group.

[blackieNYC]

Does it measure 1 diode or 4?

[Fancy Lime]

[Kevin Mitchell]

My money's on diode bridge as well.
I found one mention of a TI B498 part on a distributor's site. No datasheet though.

[puretube]

https://www.lintechcomponents.com/product/009123719/B498/01295
20V/5mA

[Rob Strand]

My first thought was a delay-line but I'm not sure if TI (from the logo) made them.   Next thought was some sort of opto.
Each lead is color coded.


Here's a few examples (mostly tapped ones) but you can see the idea and variety,

https://www.surplussales.com/DelayLines/DelayLines.html

[Phend]

Simple, plug it in.

[mozz]

 5 micro amps is what i see on those specs? I think that number B498 just happens to be a coincidence on that lintect site. To me, if it was a bridge rectifier, you would have 2 of those colored dots the same color. It most likely is samples with part numbers known to only the manufacturer and the place who ordered them.

EDIT: correct specs below, it is a rectifier of sorts.

[Rob Strand]

https://www.lintechcomponents.com/product/009123719/B498/01295
20V/5mA

That actually looks promising.

5mA could mean it is a special bridge with matched diodes for RF/mixing use.
20V could mean Schottky's (often used for RF, called "hot carrier" diodes).

[puretube]

https://www.lintechcomponents.com/product/009123719/B498/01295
20V/5mA

That actually looks promising.

5mA could mean it is a special bridge with matched diodes for RF/mixing use.
20V could mean Schottky's (often used for RF, called "hot carrier" diodes).

Those mentioned "5000 microamps" in the ad might as well be a typo that could have been 5000 milliamps, making it 5A, seen the dimensions of ~1/2" x 1/2". On the other hand those flimsy leads and their positioning don`t look like that ...

Seen the strange package and the fact of the 4 (different) colored dots, it might as well be an opto-coupler made of LED+Photodiode.

[mozz]

Specs appear to be correct, both part number matches. assigned date of 1960. Still seeing 5 micro amps.
TERMINAL QUANTITY    4
TERMINAL TYPE    WIRE LEAD
OVERALL LENGTH    0.160 INCHES NOMINAL
OVERALL HEIGHT    0.400 INCHES NOMINAL
OVERALL WIDTH    0.450 INCHES NOMINAL
ENVIRONMENTAL PROTECTION    MOISTURE
INCLOSURE FEATURE    PLASTIC CASE
RMS INPUT MAXIMUM VOLTAGE RATING    20.0 VOLTS
DC OUTPUT MAXIMUM CURRENT RATING    5.000 MICROAMPERES
LOAD TYPE    CAPACITIVE
RECTIFIER,SEMICONDUCTOR DEVICE
Part No.   B498    A25A509-005-103

[puretube]

aaah: so it is not fivethousand, but fivepointzerozerozero microampere?
Very precise limit ...

[Rob Strand]

aaah: so it is not fivethousand, but fivepointzerozerozero microampere?
Very precise limit ...

There's a stuff-up in the spec somewhere for sure.

I read it as 5mA.

Another way to stuff-up the spec is 5uA max *leakage* for a germanium diode!!!

The device looks too small for 5A.

The lintech link does classify it as a rectifier.

[iainpunk]

aaah: so it is not fivethousand, but fivepointzerozerozero microampere?
Very precise limit ...

its 5mA
5.000 thats a normal way to make 5000 easier to read in everywhere that isn't america. if it were a comma, it would have been 5 uA with lots of precision.
the website is from a company that trades across the globe, it would only be logical to use normal convention.

cheers

[mozz]

The specs i posted are from a better source IHS.  I don't know they mean by capacitive loading. It might be a typo at 5.0ua, even if it was 5ma, what use would this have?

[Rob Strand]

The specs i posted are from a better source IHS.  I don't know they mean by capacitive loading. It might be a typo at 5.0ua, even if it was 5ma, what use would this have?

I was thinking RF mixer,
https://hevirred.blogspot.com/2017/08/diode-ring-mixer.html
(low current and capacitive loading)

FWIW, TI aren't known for this type of thing but if it's a custom part ....

I also look at some old TI docs for multiple diode devices and I didn't see anything with these packages.  Things changed quickly in the 60's so that doesn't mean much.