There are also the allegro current sensing chips.  Do a google search=20
for Allegro.  It's on their front page.


Shawn Wilton
Junior in CpE
MicroBiologist

Phone: (503) 881-2707
Email: shawn@black9.net

http://black9.net

Richard.Prosser@POWERWARE.COM wrote:
> Are you actually trying to detect current in the cable or would voltage=
 be
> OK?
>=20
> The simplist way to detect AC  voltage is to wrap wire over the cable f=
or
> about 100mm or so . This will have a capacitance to the live conductor =
as
> well as the neutral & earth conductors. So a voltage divider is formed =
-
> at quite high impedance. But a couple of diodes to clip the voltage and=
 a
> connection to an input port are all that is required to detect if the
> circuit is "live" or "dead". Isolation is provided by the cable sheath =
an
> wire insulation so there is no worries here. You need an earth connecti=
on
> to your detector however.
>=20
> If you really need to detect current, then a simple magnetic detector i=
s
> probably the easiset. e.g a single or 1/2 turn  though a core with seco=
ndry
> of many turns & a load resistor. It does mean you have to split the cab=
le
> however to separate the go & return paths.
> Placing a rod type  magnetic core with 100+ turns (e.g a nail with wire
> wrapped around it !) next to the feed cable may work, depending on a nu=
mber
> of factors, but may not be reliable either, it will depend on cable
> construction, current level, length of core, number of turns... etc. I
> haven't tryed this but have used the voltage detect version above.
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> Richard P
>=20
>=20
>=20
>=20
>=20
> What is the smartest and lowest cost method to detect if there is a
> current flowing in a 110/220 V cable, preferably without doing any thin=
g
> else with the wire then to attach something outside of the cable.
>=20
> /Ake
>=20
>  ---
> Ake Hedman (YAP - Yet Another Programmer)
> eurosource, Brattbergav=E4gen 17, 820 50 LOS, Sweden
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> Company home: http://www.eurosource.se      Kryddor/Te/Kaffe:
> http://www.brattberg.com
> Personal homepage: http://www.eurosource.se/akhe
>=20
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>=20
>=20
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