What multimeter features should I consider for my circuitry projects?

[The Sand Man]

Hello Everyone,

I'm an Engineering student who has had the opportunity to work on some Mechatronics. Ever since, I've been interested in working on some circuitry for my own projects. Unfortunately, I don't have much knowledge about brands and prices, but I am looking for something that has these features:

• Accurate to at least the milli-*insert unit*
• Can plug into a regular electrical socket
• Can output its own current into a circuit

Are my demands able to be met with the maximum of a $200 budget?

Cheers,
Sand

 

[f95toli]

Any multimeter can do the first two (except measure resistance with an accuracy better than 1 mili-Ohm; which would be pretty pointless with a handheld multimeter anyway; which is what I assume we are talking about here).
I am not sure what you mean by the third? Current for measurement of current to drive something?

The main "technical" difference between cheap multimeters and and more expensive ones is the latter areTrue-RMS. More expensive ones are also usually more rugged and might have extra functions (e.g. the capability to measure capacitance, transistors etc); some can also be connected to a computer to download data.

 

[The Sand Man]

Any multimeter can do the first two (except measure resistance with an accuracy better than 1 mili-Ohm; which would be pretty pointless with a handheld multimeter anyway; which is what I assume we are talking about here).
I am not sure what you mean by the third? Current for measurement of current to drive something?

The main "technical" difference between cheap multimeters and and more expensive ones is the latter areTrue-RMS. More expensive ones are also usually more rugged and might have extra functions (e.g. the capability to measure capacitance, transistors etc); some can also be connected to a computer to download data.

Well, the ones we used in the lab had a feature where connecting a resistor to the leads gives you a reading of what resistance the resistor provides...Without connecting a battery or anything. They were the stationary desktop ones. It was a useful multimeter because we could power a circuit with a few LED lights and sensors without having a battery in the circuit.

Cheers,
Sand

 

[Integral]

Virtually every multimeter has the ability to measure Resistance. The term MULTI, implies multiple functions. Every handheld Multimeter can measure, Voltage, current and resistance.

Not sure what you mean by "plug into the wall" do you want a AC powered meter? Or one that can measure AC voltages? Not sure why you would want the former as a handheld battery powered meter is more useful, for the latter, it is an expected function of a multimeter.

Measuring milliamps and millivolts is in the expected ability of any Multimeter, milliohms on the other hand requires special instrumentation and is not found on affordable multimeters. Not a big deal however because that is not a common need.

 

[The Sand Man]

Virtually every multimeter has the ability to measure Resistance. The term MULTI, implies multiple functions. Every handheld Multimeter can measure, Voltage, current and resistance.

I know that.

Not sure what you mean by "plug into the wall" do you want a AC powered meter? Or one that can measure AC voltages? Not sure why you would want the former as a handheld battery powered meter is more useful, for the latter, it is an expected function of a multimeter.

One of the projects I'm looking to undertake is related to recharging standard batteries. I want to look at manufacturer specifications and see how they compare to the ones that I recharged. You can understand why a multimeter with the ability to output a maximum of 2 Volts would be useful. I want it to plug into a regular electrical socket because using a hand-held multimeter powered by batteries to recharge batteries sounds silly.

Measuring milliamps and millivolts is in the expected ability of any Multimeter, milliohms on the other hand requires special instrumentation and is not found on affordable multimeters. Not a big deal however because that is not a common need.

Everybody forget about milliohms, I definitely don't need to measure anywhere near that accuracy.

Here is more or less what we used in our lab:

Where should I be shopping for one of these?

Cheers,
Sand

 

[Integral]

I would not recommend buying test equipment based on the needs of a single lab. A multimeter is something that you wll use over and over in many different situations.

Most people do not expect their multimeter to double as a power supply. If you need a 2V source get a power supply to fill that need and use the multimeter do perform the measurements.

 

[Bob S]

I would look at autoranging digital multimeters similar to this ($29.99):

http://www.radioshack.com/product/index.jsp?productId=2103176#

Bob S

 

[The Sand Man]

I would not recommend buying test equipment based on the needs of a single lab. A multimeter is something that you wll use over and over in many different situations.

Most people do not expect their multimeter to double as a power supply. If you need a 2V source get a power supply to fill that need and use the multimeter do perform the measurements.

Fair enough, I'll heed your guidance!

So, what are some standard power sources? I don't want to use AA batteries, is there anything with greater output and longevity and easy ease of recharging?

Other than Radio Shack, are there any good online dealers and suppliers who ship or sell to Canada?

Cheers,
Sand

 

[Integral]

Google "bench power supply"

Find one that meets your need.

or You could put something simple together using an old appliance power supply, all depends on what you can spend and/or are comfortable with fabricating.

 

[zgozvrm]

If you need a meter that will supply a current to a circuit (a current source), along with the other "normal" functions of a multimeter, you will be looking for a something with calibration capabilities like the Fluke 789. But, for something like that, you'll be paying in excess of $800.

Even a dedicated loop calibrator like the Fluke 707 will cost you more than $600.

As for True-RMS. If you're going to be dealing strictly with sine wave signals (typical AC power, for example), you won't need true-RMS capabilities; standard meters calculate the RMS value based on the assumption that you are measuring a perfect sine wave. However, if you need more accuracy or the ability to measure sawtooth, square, or other AC signals, then pay the extra money for a true-RMS meter.

There are many true-RMS meters that run for under $200.