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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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8th Mar 2019, 3:59 pm | #21 |
Rest in Peace
Join Date: Sep 2008
Location: Solihull, West Midlands, UK.
Posts: 4,872
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Re: Capacitors in Parallel with diodes in a Bridge rectifier
Modulation hum due to the rectifier is more commonly seen (and fixed by the parallel cap) in AC/DC sets, because in AC sets the mains transformer won't pass much RF anyway.
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8th Mar 2019, 5:51 pm | #22 |
Dekatron
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,984
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Re: Capacitors in Parallel with diodes in a Bridge rectifier
Indeed; but the schematic posted was for an AC/DC set.
I agree that a mains Tx won't pass RF, but it can still inductively couple into the circuits via the mains wiring inside the set (via the fuse and to and from the voltage selector and mains switch) |
10th Mar 2019, 2:37 pm | #23 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,199
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Re: Capacitors in Parallel with diodes in a Bridge rectifier
That may not have been the only reason, at least Philips and ITT used capacitors with more modern diodes such as BY127 and BY133 as well.
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