Re: Ammeter Question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Peter Terren" <pterren-at-iinet-dot-net.au> 

To make an ammeter, I used the smallest mains transformer I could buy or
scrounge. eg old 9 v power pack. Remove the low voltage secondary windings
and discard.  Wrap 1 1/2 to 2 turns of heavy wire in place of the secondary.
When current passes through the heavy winding a voltage gets induced in the
other winding such as 10 - 50 VAC. depending on the transformer.  This is
rectified by a bridge rectifier and smoothed with a small eg 1uF capacitor.
This can be dropped with resistors to a suitable voltage for whatever spare
voltmeter you have or scale you are using. Calibrate it with a device of
known wattage eg fan heater and there you have it. Stepping up the voltage
in this way removes most of the non-linearity created by the fixed voltage
drop with the bridge rectifier. I've used this technique to keep mains power
away from the meters in my control board.
http://members.iinet-dot-net.au/~pterren/tesla_coil_latest.htm#The%20variac%20control%20box
Cheers
Peter (Tesla Downunder)

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, January 12, 2004 4:24 AM
Subject: Re: Ammeter Question


 > >Original poster: "Aaron Aab" <striker754-at-earthlink-dot-net>
 > >Where can I find an AC ammeter to go inline with my hot power supply? I
 > >would like to be able to measure the amps the transformers are drawing.