Fluke 111 Multimeter

[david7]

I have a Fluke 111 Multimeter. When I switch on to test for AC voltage I automatically get a fluctuating reading. I would expect it to read zero when not actually testing. Also the reading increases when I move my leads. Any Ideas????

[turboped]

Sounds like a problem with the connections in the leads, try tightening them up, I assume they have in line fuses in the leads, fluke leads can be awful.

[tony1941]

You don't state the size of these indicated readings. If they are quite small numbers (millivolts) then this is perfectly normal with open circuit test leads on any measurement system. You are simply looking at induced emf from all kinds of sources. If you connect the leads together, it will (should) reduce to zero (or very close to it) but it also depends on the surrounding electromagnetic fields; fluorescent lights are well known for this kind of interference. The worst place I have encountered for EMI (electromagnetic interference) is a railway environment with 25kV overhead lines. The fields are immense, to the extent that a professional voltage detector wand (lights up next to the live wire) is permanently on everywhere you go! Several years ago Raitrack (now Network Rail) issued these to all the maintenanace engineers who found that the only use for them was as a very weak battery-less torch!! Your problem is the sensitivity of digital test meters and the laws of physics. I have always liked Fluke kit, and leads are a real individual taste thing (restricted by GS38, sadly).

[tony1941]

See here for more detail, particularly table 2.
http://216.239.59.104/search?q=cache:NfkjgDOCT 94J:www.keithley.com/data%3Fasset%3D4640+&hl=e n&gl=uk&ct=clnk&cd=1

[david7]

Thanks for that tony1941. The reading goes to 0003-0002 when touching the leads together. When testing AC voltage the readings are accurate I take it the sensitivity alters the display on my meter. Just thought it may have been faulty.

[minesapint]

tony1941 is absolutely right.

All good quality meters will pick up this induced emf. I've used Eagle, Radioshack and various Fluke models in my time and they all have this problem.

To be honest, about the only place you could expect the reading to be zero is in a Faraday Cage.

[alvin100]

An analog AVO should cure the problem!!

[david7]

Alvin100 what is an analogue AVO

[Disco Fever]

It's the type with a needle giving you the readings and not in numbers like an LCD display on a digital meter.