[Amps] PS Theory ?
Skram, Helge (MED)
helge.skram at med.ge.com
Tue Sep 2 16:32:55 EDT 2003
Agree, this works fine. Mains voltage drop may be significant for multi
I have used the same method to determine the transformer resistance to use
in the PSU Designer.
Load down the transformer and measure voltage versus current. R= delta V /
73 de LA6MV
From: Ian White, G3SEK [mailto:G3SEK at ifwtech.co.uk]
Sent: 1. september 2003 16:55
To: amps at contesting.com
Subject: Re: [Amps] PS Theory ?
>** Ian -- Does the PSU Designer program have an entry for Mains
Well, kind-of. It has a little calculator where you can work out the
effective secondary resistance, which includes the real secondary
resistance plus a contribution from the primary resistance plus the
If you have a figure for mains resistance, you can add it to the primary
>How does one measure this quantity? Thanks.
1. Connect an accurate AC ammeter between the mains supply and your
biggest amp, or some other large 220-230V appliance.
2. With the load switched off, use a high-resolution RMS AC DVM to
measure the off-load voltage V1, just upstream of the ammeter.
3. Wind up to full load, and then measure the current I and the on-load
voltage V2 (which will of course be lower).
4. R = (V1 - V2)/I.
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
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