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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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12th Mar 2020, 9:33 am | #1 |
Octode
Join Date: Jan 2004
Location: Southport, Merseyside, UK.
Posts: 1,156
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Mystery 'Capacity Divider'
These three photos were taken by a friend a few years ago, they are the only photos he has and whatever happened to the instrument is unknown.
It's called a 'capacity divider' and although I can't see it having anything to do with radios as such, the BNC socket labelled 10M, 12.5PF, 12.5PF suggests something electronic. I wonder if anyone can identify this piece of equipment please? Thanks John |
12th Mar 2020, 9:52 am | #2 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,871
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Re: Mystery 'Capacity Divider'
It's a high voltage range extender for a voltmeter.
Charging a larger capacitor near ground via a smaller capacitor from the unknown voltage puts a calculable fraction of the unknown voltage on the larger capacitor. Used because it's a lot more difficult to make reliable high voltage resistors than it is to make high voltage capacitors. Used for measuring high voltage AC, can be used on dc as a one-shot measurement but that's difficult. The capacitance of whatever you feed it to and the cable are in parallel with the output capacitor and affect the accuracy, hence the design value is carefully labelled. David
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12th Mar 2020, 9:53 am | #3 |
Heptode
Join Date: Jun 2017
Location: Southport, Merseyside, UK.
Posts: 646
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Re: Mystery 'Capacity Divider'
The rounded top cap and the heavily insulated lead with the croc clip suggest something for EHT testing. Also the socket labelled 10 ( megohm? )
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12th Mar 2020, 9:54 am | #4 | |
Heptode
Join Date: Jun 2017
Location: Southport, Merseyside, UK.
Posts: 646
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Re: Mystery 'Capacity Divider'
Quote:
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12th Mar 2020, 10:07 am | #5 |
Octode
Join Date: Jan 2004
Location: Southport, Merseyside, UK.
Posts: 1,156
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Re: Mystery 'Capacity Divider'
It never ceases to amaze me how quickly these questions regarding seeminingly obscure items get answered, thank you for your replies and satisfying our curiousity.
Thanks John |
12th Mar 2020, 2:00 pm | #6 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,871
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Re: Mystery 'Capacity Divider'
S'easy! We're some very obscure people!
David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
12th Mar 2020, 2:03 pm | #7 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,871
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Re: Mystery 'Capacity Divider'
Don't tell me you're not going to put it is as a puzzle in some non-technical magazine as a puzzle "What do you think this is for?" sort of thing. With the label on the far side in the photo, of course.
The replies could be somewhat amusing. David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |