The analog meters I've seen use as little as 20uA (.00002A) for a full
scale reading. Most of the current doesn't go through the meter, but
through the shunt.
IIRC, the current through a digital meter is MUCH less.
BTW, my multimeter has a 10A range (using a low-resistance shunt). That
was one reason for choosing that meter (many were limited to 200mA).
Later I got a clamp meter that measures AC current up to 400A.
BTW2, have you ever used a clamp meter on DC?
That's a pretty impressive meter but irrelevant. The fact is that
almost all (every one you're likely to see) analog meters are current
meters at the root. The current in the coil creates the magnetic
field that moves the needle. From there, everything is scaled using
resistors into whatever voltage or current you wish to measure. A
shunt is just one such resistor used to scale the meter to measure
current. Pick your full-scale, calculate your shunt.
Not a current meter (duh!). The impedance of a digital volt-meter is
higher than an analog but you're convoluting two concepts.
Actually the current in any circuit can be higher than the meter can
handle so it is a decision to be made every time you connect.
I never cease to be amazed how little knowledge there is about
electricity amongst people risking their lives messing with it.
Bollocks. A shunt ammeter can handle hundreds of amps in series with
the load. The shunt is a very low resistance high current device, and
a voltmeter reads the voltage drop across the resistance, calibrated
email@example.com explained on 14/12/2013 :
Till you understand electricity please stop spouting rubbish.
An ammeter can only safely handle its rated current.
Yes, the shunt is a low resistance but it is only big enough to handle
the rated current.
ie a 5 amp meter will have a shunt or be intenally capable of carrying
5 amps plus a margin for overload safety.
It will explode at "hundreds of amps"
Actually Sandy has an itchy butt which I see her dragging on the rug.
She just now came up to me and put her tiny paws on my thigh to get my
attention. She wanted in my lap or for me to get her comforter off the
loveseat to put on the floor next to me so she could burrow under it. ^_^
On Fri, 13 Dec 2013 13:27:38 -0500, Stormin Mormon
I just make a short extention cord and split the external sheath,
allowing the insulated conductors to separate so you can install the
clamp-on meter. About $3.
so the microwave was on the same circuit as a coffee maker. breaker tripped frequently when both devices were on
this damaged the breaker, they are designed to get more sensitive as they age or wear.....
so now normal operation is tripping the breaker.....
i bet you will find they need a new breaker.... this is a common failure mode for breakers
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