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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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12th Aug 2020, 9:03 am
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#1 |
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Pentode
Join Date: Oct 2009
Location: Holbeach, Lincolnshire, UK.
Posts: 134
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Multi leg capacitor polarity
On these old multi leg capacitors which leg is +ve? This one is a 50uF + 50uF and has one broader terminal but no identifying markings, no paint spots or anything. Am I correct to assume that the bigger terminal is a common -ve connection
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12th Aug 2020, 10:17 am
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#2 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Multi leg capacitor polarity
Larger terminal = common -ve
Yellow? terminal = 50uF (inner....HT filter) Other terminal = 50uF (outer....HT reservoir) Would be my first thoughts. Lawrence. |
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12th Aug 2020, 10:29 am
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#3 |
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Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
Posts: 3,323
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Re: Multi leg capacitor polarity
There are what appears to be paint on two of the terminals. Yellow and red on the two on the right. The more separated one looks unmarked. Test with a capacitance meter.
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12th Aug 2020, 1:01 pm
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#4 |
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Pentode
Join Date: Oct 2009
Location: Holbeach, Lincolnshire, UK.
Posts: 134
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Re: Multi leg capacitor polarity
No paint spots (unusually) just flux deposits. My meter (Fluke 87) shows "out of range" I have a feeling it is limited to 10uF or something so I can't test them that way.
Next silly question...If I bridge the 2 thinner terminals together will it give me double the marked rating? I can never remember whether its series or parallel.Its only for an experimental/prototype project and will get replaced with a "proper" one if there are signs of life. Circuit specifies 220uf but I have some of these 100+100's and 50+50's lying about. |
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12th Aug 2020, 1:28 pm
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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: Multi leg capacitor polarity
Yes if the bridge results in a parallel combination, then it will double the capacitance so > 100uF
David |
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12th Aug 2020, 1:59 pm
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#6 | |
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Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,600
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Re: Multi leg capacitor polarity
Quote:
I see there are various versions of the Fluke 87, one (V) goes up to 1,000uF and another (IV) goes right up to 50mF (50,000uF) so yours must be a lower spec version. David |
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12th Aug 2020, 3:16 pm
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#7 |
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Pentode
Join Date: Oct 2009
Location: Holbeach, Lincolnshire, UK.
Posts: 134
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Re: Multi leg capacitor polarity
It's an oldish one, I got it from an MoD surplus sale years ago.
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