Multimeter useful for PWM analysis and arduino

Subcject: Multimeter frequency, duty cycle, Min Max, peak, and true RMS features

Hi!

I'm seeking any advice on what multimeter I should get for troubleshooting PWM circuits*** and (in the future) arduino tinkering . I do know that the right tool for the job is an oscilloscope but I won't be able to bring any oscilloscopes to my house anytime soon so please don't recommend getting one. After watching several videos on the subject on youtube I think I get the basics. Protection (I don't need anything better to what they put in all those cheapo meters), precision, basic functions etc. but I don't know whether the features listed above would be useful for troubleshooting e.g. this PWM circuit:
article http://www.overclockers.com/pwm-fan-controller/
description of the issues I have with the circuit http://www.overclockers.com/forums/...for-PWM-Fans?p=7871279&viewfull=1#post7871279

My choice regarding brands is very limited. Taking into account the availability I have narrowed down my preferred choices to two UNI-T UT61 series true RMS multimeters - UT61D and UT61E:
http://uni-trend.com/HDM_UT61.html
D has Min Max while
E has peak only

If all of those functions are useless for PWM troubleshooting I'm simply going to another basic multimeter.

***an incomplete set of relevant parameters is fine by me

I'd appreciate any input on this guys.


http://www.prweb.com/releases/2011/1/prweb8085843.htm
http://cr4.globalspec.com/thread/77147
How to Measure Frequency And Duty Cycle With A Multimeter - YouTube

if you can't afford a scope, why not look on the used market for a vantage, it's used for automotive but just might fit what you are looking for.

Some multimeters can measure frequency and duty cycle.

caddi daddi said:

if you can't afford a scope, why not look on the used market for a vantage, it's used for automotive but just might fit what you are looking for.

Click to expand...

It's mainly about the limited space I have available, not the money.

NiHaoMike said:

Some multimeters can measure frequency and duty cycle.

Click to expand...

Would a standard meter with frequency measurement actually be able to measure frequency of a square wave? What about the other features I mentioned. Would they be useful to get an idea of a PWM signs characteristic?

To an inexperienced person like me having frequency and min max feature at hand is obviously enough to achieve this. The problem is... the practical use. Will a multimeter measure reliably, let's say within +/-5%? Will the said features even work on a PWM signal? This is the kind of problem I'm facing.

I know for a fact that people use duty cycle measurement for checking LED light drivers but I haven't seen anything Tha would mention the rest of the features in question.

Brutal-Force said:

Click to expand...

That's when it's already an affordability issue
To put things into perspective the meter is around $220 in Poland, it is not uncommon that a fresh engineer earns less than $800 a month while paying $300 for a small flat in a major city.

It wouldn't be a shoddy Christmas gift though

I would really appreciate if anyone drops an additional thought about peak vs min max usefulness. In general:
UT61E is my max price cap
UT61D if peak is not useful
UT61C if true RMS is not useful

What about a DSO nano? It's not a particularly good scope but it is cheap and small enough to fit in your pocket.

NiHaoMike said:

What about a DSO nano? It's not a particularly good scope but it is cheap and small enough to fit in your pocket.

Click to expand...

Since I need a new multimeter anyway that would still be too expensive for now. But thanks for the hint! I'll take a note for later. I have only found DSO NANO DSO201 for $75 which I would put against a $55 second-hand bulky analog oscilloscope. But again, this is for future thought. EDIT: Plus DSO Nano v3 https://elty.pl/en_US/p/OSCYLOSKOP-DSO-NANO-V3/592

So, per the topic, are you saying that apart from frequency a true RMS multimeter with min and max is not going to tell me anything more about a PWM signal apart from frequency and duty cycle?

How To Use The Delta Relative Function On A Multimeter - YouTube
Towards the end of the video there is something about using peak feature for square wave.

It seems to me that the key to answering my original question may be the actual response time of the min max feature. See here Min/Max/Average Demo - Fluke 287 & 289 True-rms Logging Multimeters with TrendCapture - YouTube 100 ms would mean 10 Hz sampling i.e. useless for PC fan PWM analysis which is ~20 kHZ square wave per the whitepaper if I remember correctly. Here's where the peak should come in handy.