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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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24th Nov 2021, 12:28 am
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#1 |
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Nonode
Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,330
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Another "what is this?" thread. Air Ministry?
A substantial metal can in what I would consider an Air Ministry blue. No markings. Red/Black/Blue wires from one grommetted hole; Red/Blue + screen from another. Blue and Screen to a ring connector. 2k ohms from Red to Blue + Screen. The other three wires read as a diode pair on my component tester: Blue shared anode, Black and Red the two cathodes.
The rear cap can be removed by taking out three screws, and there's a sealed paxolin base with two Hunt's capacitors inside. No doubt someone will immediately give its exact purpose! 
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24th Nov 2021, 5:37 am
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#2 |
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Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
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Re: Another "what is this?" thread. Air Ministry?
Looks to me like a matching transformer. More specifically ( but, I am guessing ) a microphone transformer. Are they capacitors? or resistors?.
Regards Joe |
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24th Nov 2021, 9:59 am
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#3 |
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Nonode
Join Date: Mar 2010
Location: Dukinfield, Cheshire, UK.
Posts: 2,036
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Re: Another "what is this?" thread. Air Ministry?
I think Joe has probably got it. It has the look of an audio transformer or maybe RF. Or there is the chance that it's a frequency standard. The multiple leads might indicate the presence of an oven.
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Andy G1HBE. |
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24th Nov 2021, 10:46 am
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#4 |
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Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,531
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Re: Another "what is this?" thread. Air Ministry?
My thought was also a microphone transformer, like this one:
https://uk.rs-online.com/web/p/audio...ormers/2106352 |
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24th Nov 2021, 11:17 am
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#5 |
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Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,600
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Re: Another "what is this?" thread. Air Ministry?
One example of a microphone matching transformer from one of my Grundig tape recorders.
David |
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24th Nov 2021, 12:50 pm
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#6 |
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Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,269
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Re: Another "what is this?" thread. Air Ministry?
I thought mic transformer too but the report of diode junctions put me off.
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Kevin |
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25th Nov 2021, 7:17 pm
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#7 |
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Nonode
Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,330
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Re: Another "what is this?" thread. Air Ministry?
I'll stress the diodes was only what my tester thought they were! I've now tested it with a multimeter and get ~20 Ohms on both polarities between black and blue so it's not actually a diode junction. Also 20R between Blue/Red and 40R between Black/Red.
I would have to split the seal around the paxolin base to try and prise out whatever it is. The ring terminal has continuity to two of the pins inside the removable cap: the one not connected to the capacitors, and one of the ones the capacitors are connected to. There is no continuity to the case. The capacitors are 0.0022µF and 0.0033µF, both 500V. |
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25th Nov 2021, 8:18 pm
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#8 |
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Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,858
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Re: Another "what is this?" thread. Air Ministry?
Not many things need a can that thick. I suspect it's a magnetic screen, and that points to small signal audio use. Microphone transformer most likely.
David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
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