fluke multimeter

[Brendon Warren]

I just picked up this multimeter from my cousin yesterday. Her husband passed away and I bought some tools from her. Fluke 112 True RMS multimeter. Now I just need to figure out how to use it. Its brand new in the box, directions were still in cellophane. Any ideas on what one would cost new? I'm no electrical wizard so I guess I better read the book.

 

[87nassaublue]

It sounds like a pretty nice meter. You can do a google to get a retail price. Ebay can tell you what you can sell it for. Back about 3 decades ago, a true RMS meter would be around $400. I bet they are a lot cheaper now.

 

[johnpop1]

probably around 110-120 would be my guess

 

[WvaJim]

Fluke no longer makes that model, one similiar, a 114. Some places on the net that had some old stock left was about 170 plus shipping. Ebay had one for 70 bucks but no leads an cover missing.

 

[Paul from MI]

Fluke is a high end meter, probably around $200 new.

 

[Billy Shafer]

The 112 is no longer made. But I would guess around 200.00 with case. The last time I turned in a obsolete Fluke. For cleaning and calibration.They replaced it with an updated model for free.

 

[J. Schwiebert]

What all scales are on that meter? RMS =Root Mean Square! You can measure surfaces finishes.

 

[Mike(NEOhio)]

Fluke is excellent quality. We used them in a welding lab and they can take quite a beating.

 

[Brendon Warren]

To tell you the truth I haven't a clue how to use it. I think I figured out continuity and it shows that a double A battery has 1.5 volts. My buddy is an electrical inspector maybe he can show me what its for. Until this point I've had a test light made from a license plate bulb. Just call me Bubba.

 

[: JerryBowers]

Yes, RMS does mean Root Mean Square. In the case of surface finishes it means the mathematical root mean square of the micro deviations on the surface, usually left by some machining operation like a lathe.

In the case of a volt meter, it means the mathematical Root Mean Square of AC electric voltage. The Fluke meter under discussion measures voltage, not surface finish.

 

[: JerryBowers]

You have an excellent precision voltmeter. IMO, Fluke meters are really the best performing high-end meters on the market.

The Fluke 112 (now superseded) originally listed at something over $250. I bought one a year or two ago for ~$200. Some new, old stock ones occasionally show up for something between $150 & $200, used for ~$100 and up.

 

[ShadetreeRet]

You have a brand new high quality tool there, by all means read the instruction booklet! When using electrical instruments such as that, one bad connection can fry the thing, (if it is a cheap unit), or blow the fuse, (if it is a quality unit.) Don't ask how I know. And, as you say, maybe your friend can school you on it. Google may even be able to help.

 

[jeffcat]

Please do not get me wrong!!! This is toooooo nice of a meter if you don't know how to use it. Sell it on Flebay and just buy a HF $30.oo meter that will do everything you need and someone else will have bought a meter that they do know how to use. Like the story of someone getting hold of a beauty of a chainsaw and putting regular gas it it! I have a Fluke 179 that cost even more. I actually use both the RMS and the frequency functions in it. Great for setting a home generator at 60hz on the nose!! jeffcat

 

[Hobo,NC]

(quoted from post at 04:40:10 03/10/15) Yes, RMS does mean Root Mean Square. In the case of surface finishes it means the mathematical root mean square of the micro deviations on the surface, usually left by some machining operation like a lathe.

In the case of a volt meter, it means the mathematical Root Mean Square of AC electric voltage. The Fluke meter under discussion measures voltage, not surface finish.

http://www.edaboard.com/thread197127.html

http://en.wikipedia.org/wiki/Root_mean_square

 

[Indiana Ken]

I have an old school electric clock on the wall with three pointers that go around and around. I can use it to tell me when my generator is fast or slow. When I plug it back in the wall it can tell what time it is. The lighted dial provides a nite light for the shop. Can your fancy meter do all that...LOL

 

[MarkB_MI]

That's a fine instrument.

Most multimeters use "peak averaging" to calculate ac voltage. They measure the peak-to-peak voltage, divide that by two, then divide that number by the square root of two. So a 120 Vrms sine wave has a peak voltage of 170 volts, or 340 volts peak-to-peak. Peak averaging is a very accurate way to measure a clean sine wave, but it won't be right for a non-sinusoidal wave form. If there's a lot of noise on the signal, for example, peak averaging will read high. On the other hand if your measuring a square wave, peak averaging will give you a value that's only seventy percent of the true rms value.

What root-mean-square does is to tell you how much POWER a waveform can provide. It's really the equivalent DC voltage for any waveform. For example, if I apply 10 volts DC to a 10 ohm resistive load, I will get 10 watts out (V²/R). If I apply a 10 volts rms to the 10 ohm load, I'll still get 10 watts, irrespective of the waveform or peak-to-peak voltage.

 

[RodinNS]

I don't have that particular meter but some I've seen would run in the 3-400 range here for cost. Mabey more..

I would read the book. It should explain all the features quite effectively. I would not trade it for all the 30 buck HF meters in the world. You have a very good, accurate meter there. That's important every once and a while..

Rod

 

[El Toro]

We used Fluke data loggers for recording temperatures. Sure beat the old Brown recorders. Hal

 

[Texasmark1]

Root Means Square (RMS) is what most AC meters measure......takes the square root of the squares of the average values.........same as the heating effect of DC and is why it's used. You can't read the average value of AC as it swings equally above and below zero thus the average is zero. Then there is the "effective" value of AC and I forgot what that is (67% of peak???) as it is seldom used.

Don't know about Peak Averaging. There are Peak reading meters whose job it is to read the absolute peak value where things like the peak voltage rating of components is an issue. The meter has a sample and hold circuit that samples the peaks, and that includes peaks of ignition systems trigger circuits which are short bursts of voltage with long rest times between, and holds(stores.....adds them together) them so that there is enough power to drive the display.

Mark

 

[Hobo,NC]

(quoted from post at 18:04:15 03/17/15) Root Means Square (RMS) is what most AC meters measure......takes the square root of the squares of the average values.........same as the heating effect of DC and is why it's used. You can't read the average value of AC as it swings equally above and below zero thus the average is zero. Then there is the "effective" value of AC and I forgot what that is (67% of peak???) as it is seldom used.

Don't know about Peak Averaging. There are Peak reading meters whose job it is to read the absolute peak value where things like the peak voltage rating of components is an issue. The meter has a sample and hold circuit that samples the peaks, and that includes peaks of ignition systems trigger circuits which are short bursts of voltage with long rest times between, and holds(stores.....adds them together) them so that there is enough power to drive the display.

Mark

This is what I have in my notes from 1994...
Automotive use

Fluke 87) All GM use RMS - AC spec for AC voltage .707

Fluke 88) Everybody else say use average speck .640

That its ever made a difference to me a average Joe...

 

[Texasmark1]

RMS is .707 x the peak for a sine wave, not for a complex
waveform.

Average is zero as I said. Every 60 seconds you have 360 plus
half sine waves and 360 Identical but minus half sine waves
alternating one after the other. The algebraic sum, averaging, is
zero.

640 sounds about right for effective voltage which I forgot it's
usage.

Mark

 

[Texasmark1]

Scuse me, arithmetic error. 60x60 is 3600, not 360.