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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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29th May 2023, 1:01 pm
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#1 |
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Hexode
Join Date: Feb 2008
Location: Wrexham, North Wales, UK.
Posts: 465
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Mystery transformer
CAn anyone identify this odd transformer?
It's marked A M Ref No. 10K/13259 Four terminals marked IP OP IS OS - meaning obvious! DC resistance primary 4.5 ohm, secondary 1250 ohm. Turns ratio roughly 30:1. The turns ratio is too high for an intervalve Tx, the resistance readings are the wrong way round for an output Tx. Perhaps a matching Tx? But for what? |
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29th May 2023, 1:04 pm
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#2 |
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Dekatron
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,980
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Re: Mystery transformer
Picture of the item might help
Craig
__________________
Doomed for a certain term to walk the night |
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29th May 2023, 1:28 pm
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#3 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Mystery transformer
IP = Plate
IO = B+ IS = Bias -ve IO = Grid. https://www.vintage-radio.net/forum/...d.php?t=152667 Lawrence. Last edited by ms660; 29th May 2023 at 1:39 pm. Reason: link added |
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29th May 2023, 2:08 pm
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#4 | |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Mystery transformer
Quote:
IP =B+ OP = Plate IS = Bias -ve OS = Grid. Lawrence. |
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29th May 2023, 4:23 pm
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#5 |
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Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,996
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Re: Mystery transformer
As others have suggested , could this be an input transformer for use with a carbon microphone??
The step up ratio would be good to deliver a nice voltage swing to the grid of an intercom or low power transmitter modulator.
__________________
I'm the Operator of my Pocket Calculator. -Kraftwerk. |
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29th May 2023, 6:12 pm
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#6 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Mystery transformer
Mods permitting for possible ID purposes only, I wonder if the transformer in the schematic that's shown in the link below for the Air Ministry Type I Microphone Tester could be a contender? (I've not seen the innards of one):
https://mullardantiques.co.uk/produc...de-by-ferranti Lawrence. |
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29th May 2023, 6:21 pm
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#7 |
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Nonode
Join Date: Jun 2010
Location: Spalding, Peterborough, Cambridgeshire, UK.
Posts: 2,858
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Re: Mystery transformer
A picture next to a ruler would help identify possibilities of use.
Rob
__________________
Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd |
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29th May 2023, 7:36 pm
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#8 |
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Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,652
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Re: Mystery transformer
I looked up 10K/13259 in AP1086. This is the description it gave:
"10K/13259 Type 870 ... ... Primary, 200 turns of 34 S.W.G. wire. Secondary, 700 turns of 42 S.W.G. wire." So the turns ratio is 7:2, not 30:1 as you describe. Did you measure the transformer yourself? If so, I suggest double checking your measurement method.... Your resistance figures are no doubt right, so it could well be an intervalve transformer. My copy of the 10K section is dated 1943, so I suppose its possible that a rather antiquated component could still be listed at that date. Richard |
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29th May 2023, 10:07 pm
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#9 |
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Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
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Re: Mystery transformer
I provided the details of this transformer from AP1086 Section 10K when the OP first asked the question in 2018.
The link provided by Lawrence in post #3 refers back to the 2018 thread. Andy |
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30th May 2023, 10:29 am
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#10 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Mystery transformer
The transformer in the Type 1 Microphone Tester I mentioned earlier can be eliminated, the ref. for the one fitted in the tester is 10a/3365.
Lawrence. |
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