Alt-BEAM Archive
Message #00432
To: beam@corp.sgi.com
From: "Sathe Dilip" sathe_dilip@bah.com
Date: Mon, 15 Feb 1999 11:52:57 -0500
Subject: [alt-beam] Re: determining current
Victor Snesarev wrote:
>
SNIP
> Second method. If you only have a voltmeter, you can measure the voltage
>across a resistor and then use the formula I = V/R (current=voltage over
>resistance) to figure out current through the resistor.
> Any other methods?
>
> Victor
Just for sake of completeness:
For measuring AC currents, current transformers (CT) are used. The
primary winding of the CT has to be wired in series of the circuit
segment in which the current is to be measured. Some of these (CTs) are
non-contact type like in a clamp meter - you do not have to break the
circuit and insert the meter in series - just wrap the clamp (which also
forms the core of the transformer) of the meter around the conductor
carrying current to be measured. The conductor passing through the core
acts as the (partial turn) primary winding.
There are similar non-contact current measurement probes for DC as
well. Some of these are based on the Hall effect in semiconductors.
Dilip
--
Pl. remove *s from the e-mail address to reply
------------------------------------------------------------------------
eGroup home: http://www.eGroups.com/list/alt-beam
Free Web-based e-mail groups by eGroups.com
Home