No sir - off line switchers need large input smoothing caps for 2 reasons.
1. To hold up the supply for several dropped mains cycles.
2. To reduce the ripple on the raw DC to prevent sub-harmonic operation.
These types of caps have low esr and can handle oodles of ripple current at
50kHz and
upwards. Don't forget that although the mains supply produces a 100Hz/120Hz
ripple
component, the switching device draws very large peaks of current at the
switching
frequency.
John ZS5JF
----------
> From: measures <measures@vcnet.com>
> To: ohashi <ohashi@ny.airnet.ne.jp>; AMPS <amps@contesting.com>
> Subject: Re: [AMPS] Alminum Capacitor
To: <amps@contesting.com>
> Date: 15 September 1999 06:20
>
>
> >
> >Greetings from Japan !
> >
> >I got 8 pcs of Aluminum Capacitors (Not used JUNK) at
> >Japanese HAM FAIR last month.
> >
> >The printing on the capacitor is as follows;
> >
> >560uF 450V, 105 degree C, MKH
> >Nippon Chemicon
> >
> >Surprisingly the size is very small (35mm dia and
> >50mm height).
> >I guess this is designed for Bulk Capacitor
> >in Switching Mode Power Supply.
> >
> My guess is that they are intended for 50/60 Hz service. Switccher
> supply caps would need much less C and very low ESR.
>
> - Rich..., 805.386.3734, www.vcnet.com/measures.
>
>
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