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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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20th Sep 2019, 11:54 am | #1 |
Heptode
Join Date: Apr 2003
Location: Ayr, Ayrshire, UK.
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Texas Instruments Bridge Rectifiers
Hi,
I came across these 35mm square bridge rectifiers amongst a stash of components I got at a 'junk' sale. Given their size and type numbers (1B20K10 & 1B20K20) I had hoped they'd be rated for 20A or so. However, I've just found out from an on-line datasheet that they're only rated at 2.0A ! If this is correct I can't understand why they're so BIG ! Any thoughts ? Andy
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20th Sep 2019, 12:10 pm | #2 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
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Re: Texas Instruments Bridge Rectifiers
They are very old designs. I seem to remember one of these in a Roband PSU from around 1962.
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20th Sep 2019, 12:51 pm | #3 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Texas Instruments Bridge Rectifiers
Back when they were made, anything for high voltage was much bigger than it was today.
Also, that series ranged from 50 to 800volts (all at 2A), so it was probably a standardised package of the time. |
20th Sep 2019, 1:53 pm | #4 |
Heptode
Join Date: Apr 2003
Location: Ayr, Ayrshire, UK.
Posts: 630
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Re: Texas Instruments Bridge Rectifiers
OK fair enough, I didn't realise that they were that old, they must be early silicon types.
Thanks for the comments. Andy
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20th Sep 2019, 3:10 pm | #5 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
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Re: Texas Instruments Bridge Rectifiers
A 20 amp device would probably be in a metal case.
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20th Sep 2019, 4:45 pm | #6 |
Heptode
Join Date: Mar 2010
Location: Eastham, Wirral, Merseyside, UK.
Posts: 788
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Re: Texas Instruments Bridge Rectifiers
HI, Radioman,andy.
Would a 25A be Suitable for you, have a look at Data sheet 26MB60. they are not cheap but if you really need them I will send you two Nos/FOC. you pay postage. PM your address Gezza123 |
20th Sep 2019, 6:14 pm | #7 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Re: Texas Instruments Bridge Rectifiers
some of the early bridges were just potted-up wire-leaded diodes - note the turret tags. More a convenience item than anything special.
Beefy ones need heat sinking, with an aluminium outer case or just an aluminium base. Plessey moulded some onto short bits of aluminium angle (and did a similar audio amp... I think Clive got the rejects ) David
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20th Sep 2019, 9:53 pm | #8 | |
Heptode
Join Date: Apr 2003
Location: Ayr, Ayrshire, UK.
Posts: 630
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Re: Texas Instruments Bridge Rectifiers
Quote:
Thanks for that offer but I don't need one with that high a voltage rating. I was only trying to identify what I had acquired and confim the specification. I'm sure I've already got a 25A one somewhere - just need to find it ! Cheers, Andy
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21st Sep 2019, 2:56 am | #9 |
Moderator
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Re: Texas Instruments Bridge Rectifiers
The diodes in early bridges are often quite slow types and prone to generate broadband RF noise. It sounds bizarre, but they can be noisier than an SMPS.
David, (G-QRP 3252)
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21st Sep 2019, 8:05 am | #10 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
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Re: Texas Instruments Bridge Rectifiers
And only 200v PIV which is a shame, still they'd be ok for small low powered circuits though the turret tags mean they can't really be mounted on a board, still worth keeping though.
I have some of the older diodes and looking at the specs of a lot of them, they really are c**p, EG 40v 400mA. Diode/rectifier tech has come a long way since. Andy.
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21st Sep 2019, 10:51 am | #11 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
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Re: Texas Instruments Bridge Rectifiers
Absolutely - OA211 - 0.5 amp, Stud mounted!
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21st Sep 2019, 11:21 am | #12 |
Nonode
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 2,321
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Re: Texas Instruments Bridge Rectifiers
They can be pcb mounted, but you need some really big holes
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21st Sep 2019, 2:27 pm | #13 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,381
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Re: Texas Instruments Bridge Rectifiers
Poor wee (or not so wee) bridges. Not many amps, not many volts for their size and likely to be noisy.
Packing washers? Or just steering gates in a low-power dual supply application. |
22nd Sep 2019, 11:55 am | #14 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
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Re: Texas Instruments Bridge Rectifiers
1B40K20: 4 amps, 200 v. I have a bag of 15 of these, none of which I have used for decades - and I don't anticipate that I will be using them - ever. Some have been used; some haven't (no solder on their tags).
Free to anyone who wants them: you pay for the postage only. Replies by P.M., please. Al. |
23rd Sep 2019, 8:27 am | #15 |
Heptode
Join Date: Apr 2003
Location: Ayr, Ayrshire, UK.
Posts: 630
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Re: Texas Instruments Bridge Rectifiers
I've got a couple of the 4A ones as well... so no need here.
Perhaps you should advertise them in the 'Offered' section of the Forum, I'm sure someone will want them ! Andy
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23rd Sep 2019, 9:00 am | #16 |
Octode
Join Date: Feb 2018
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Re: Texas Instruments Bridge Rectifiers
Would a 3N255 be noisy too ? I've one or two pulled ones that I'm hoping to use in my project.
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23rd Sep 2019, 1:11 pm | #17 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Texas Instruments Bridge Rectifiers
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23rd Sep 2019, 1:26 pm | #18 |
Moderator
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Re: Texas Instruments Bridge Rectifiers
It depends what you call noisy. They will be fine for some applications, but not others. Fast diodes are very cheap, so it's a mistake to use old scavenged parts if noise is likely to be an issue.
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