Alt-BEAM Archive
Message #01680
To: Jacob Booth J.Booth@mackillop.acu.edu.au
From: Steven Bolt sbolt@xs4all.nl
Date: Mon, 22 Mar 1999 14:59:33 +0100 (CET)
Subject: [alt-beam] Re: Ripple current and Goop problem
On Sun, 21 Mar 1999, Jacob Booth wrote:
> 1. what is the term 'ripple current' meaning in relation to capacitors? I
> have a catalog here and one of the specs for these caps is there 'ripple
> current'. Any ideas?
Caps are commonly used as part of the low pass filter in power
supplies. You typically have a transformer, followed by a rectifier
and a largish electrolytic capacitor. The transformer reduces the
alternating mains voltage to a lower value. The rectifier turns it
into something wich stays on one side of ground, but is still
modulated by the mains frequency. Add the capacitor and you get
proper DC - as long as there is no load on the power supply. A load
will cause the modulation to re-appear as `ripple'. The size of
that ripple is determined by the value of the capacitor and by the
load.
A stabilizer following the cap may cut the voltage from for
instance 9V to 5V. Almost no ripple will appear in its output, as
long as the ripple on the input isn't deeper than 9 - 5 + the
voltage difference needed by the stabilizer, often something like
3V.
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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