what multimeter to buy?

[nuclearlemon]

great thread considering i'm dealling with electrical drain on my 80. po put a ford fuse block in right off the battery (that's the issue...ford), and i've got a serious enough drain that it will drain a freshly "conditioned" battery enough that by friday, with a 25 minute daily drive to work and then home i won't have memory on my radio

tried to test the draw with a harbor crap meter and it showed 0. i have a 95 fzj80, so i know damn well there better be something between radio and computers. one of the techs at work loaned me one of his meters and i found the issue. i've always used cheap meters because i can't see spending $150 on something that i have no clue how to use (like many, i'm an electrical idiot), but they failed me in a test i actually knew how to run. they're great for reading volts and ohms, but apparently can't handle amps.

here are pics from my before i narrowed down which fuse and the after. this is off the amp setting (not milliamps)

this was a mac branded meter. and for idiots like me, you had to have it in the correct setting on the dial before you could insert the little probe thingy.

 

[Elbert]

If you want a life long tool that is of good quality get the Fluke..... I have two.. but one of those has been with me from the late 80's.

 

[e9999]

as stated elsewhere, the HF meters are either free (I got several) or about 1/4 of the cost of a Fluke meter fuse (!), so not a bad idea to use one for amps check before you use your good meter if you're not sure what current you're dealing with. (there is a thread out there about the vagaries of amps measurements and the Poof effects for the memory-challenged backyard electricians... )

 

[nuclearlemon]

as stated elsewhere, the HF meters are either free (I got several) or about 1/4 of the cost of a Fluke meter fuse (!), so not a bad idea to use one for amps check before you use your good meter

except i started with a freebie hf meter and it showed no amp draw.

 

[agaisin]

except i started with a freebie hf meter and it showed no amp draw.

I hate to see anyone badmouth a crappy multimeter

So in the spirit of fairness, chances are at some point you or someone you lent it to accidentally shorted it (measured amps across pos and neg terminals) or overloaded it beyond it's capacity. if your meter was complete crap it had no fuse and blew permanently. if it was at least a step up from a turd it had a fuse that you should be able to replace. i think blown fuse on some models would give 0 amps when they're blown.
if you're like me and didnt know that at first, i cursed my meter and later realized it's by design, just a fuse i can replace...

 

[nuclearlemon]

but volts and ohms work. i'd assume those would go when the fuse blew

i have blown up the hf meters (don't change settings while the probes are hooked up) and it goes completely dead. this meter isn't dead

 

[agaisin]

but volts and ohms work. i'd assume those would go when the fuse blew

i have blown up the hf meters (don't change settings while the probes are hooked up) and it goes completely dead. this meter isn't dead

On the ones I've used so far, i could still read volts after fuse was blown. i assume it has todo with what else is on the fused port?

the few i've been toying with have 1 com, 1 for Amp readings (10A fused), 1 for mA readings (smaller fuse like 400 or 440ma), and then the V and everything else port. So for example, blowing the 440ma fuse only effects mA readings, blowing the 10A fuse only effects Amp readings but even with both those fuses blown the other functions work (based on my limited experience/understanding).

 

[george_tlc]

Multimeters measure current by measuring the voltage drop across a known small value resistor inside the meter. Separate resistor for the 10A range versus the lower current ranges.

Any 1/2 decent meter will have 2 fuses to protect the small value resistors, the leads and other expensive bits. One fuse for the 10A range and a smaller value fuse for the lower current (typically <1A) range.

If you measure currents that exceed the fuse (like having you meter on the amps range and measuring across the battery etc....) the fuse will blow to protect the other expensive bits.

With the blown fuse, the current path through the small value resistor no longer exists and you can't measure current. The voltages and ohms are a totally separate path that are NOT fuse protected since they are high impedance and can't draw more than uAmps.

If you plan to measure unknown or high current paths, a DC clamp meter is a much better & safer idea and you don't need to disconnect battery leads etc.

Fluke meters are my first choice. Like any tool, if you plan to use it once or twice, then something cheap makes sense, if you plan to use it for many many years and not have it break when you REALLY need it - spend the $$ once.

A decent Fluke will BEEP if you rotate the meter away from the amp range to one of the voltage/resistance ranges (while leaving the probe still plugged into an Amp input) to remind you of the risk of blowing a fuse on your next measurement....

Cheap meters have their place, but certainly not at my place...

cheers,
george.

 

[Pin_Head]

Just to be pedantic: The main difference between the cheapo and expensive meters is sensitivity and accuracy. When you measure a voltage in a circuit, you are changing the load on that circuit and that can change the observed voltage via Ohms law. Expensive meters have sensitivities of 50,000 ohms per volt or more. The accuracy depends on the tolerance of the resistors used, 1% vs 5%.

The amp, volts and ohms circuits are different and work independently. That is why they have a switch to change functions and range.

 

[Healey]

Simpson 260

 

[LandCruiserPhil]

Simpson 260

The industry standard back in the day

I have several including this from 1901

 

[Healey]

Wow. Very cool pic - thanks for posting.