# What is this weird Multimeter setting?



## Bonky (Feb 18, 2009)

Just got a new cheapy DMM from ebay for testing my lights, and it has the following setting that was undefined in the 'manual' that came with it. Never seen it before on a DMM. Can anybody tell me what this is/used for?

***image deleted

Thanks!


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## odessit (Feb 18, 2009)

maybe it is frequency?


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## 65535 (Feb 18, 2009)

I agree looks like a setting to measure frequency. Most meters us Hz but you never know.


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## Illum (Feb 18, 2009)

maybe its like an oscilloscope, that function allows you to test the waveform of either a drive circuit, or the output condition, usually used for things that are cycling, like boost/buck ICs.

Don't ask _Mr. Happy_, he doesn't know the details


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## PeAK (Feb 18, 2009)

Bonky said:


> .
> .
> .Never seen it before on a DMM. Can anybody tell me what this is/used for?
> .



On my equally inexpensive DMM, it outputs a 2V peak square wave at 30 Hz. The amazing thing about the meter is that it measure to within 2mV of my more expensive meter...so cheap can be good...especially in the era of ICs.

P.S. When the "battery low" indicator comes on, I used another meter to find the battery was putting out 7.4V. Replacing it with an adjustable power supply, I found that the readings were consistent from 9V down to 6.4V...great design!!!

PeAK


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## dilbert (Feb 18, 2009)

Looks like the square wave symbol :shrug:


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## Wattnot (Feb 18, 2009)

Yeah, it looks like a square wave generator. I'm not sure what it's used for . . . maybe calibrating an oscilloscope?


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## TakeTheActive (Feb 18, 2009)

Bonky said:


> ...it has the following setting that was undefined in the 'manual' that came with it. Never seen it before on a DMM. *Can anybody tell me what this is/used for?*


Connect a (disposable / inexpensive / EXPENDABLE) 8 ohm speaker to the meter leads and see if you hear a tone. :thinking:

If you do, you can use that setting for tracing wire pairs. For example, you have several UNLABELLED CAT5 cables terminating in a basement utility room coming from all over the house. Put a 'tone' on a pair and take a speaker around the house to 'listen' for continuity. With just a 'plain old-fashioned VOM', you could SHORT a pair in the utility room and then check for 'not infinity' around the house.

Maybe? 

What did you pay for it, what size battery does it use and what are the 'specs'?


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## Bonky (Feb 18, 2009)

You're going to laugh.. I got it from ebay for about $16 including shipping. The meter itself is labeled a "FTIKE" but on the packaging it's called "ALSABEK." I got it because it was one of the few cheapies that was NOT being shipped from HK, (wanted something fast.)

PeAK seems to have the same one, since mine uses a 9V battery but in the instructions mentions a "7V" battery.. so it appears it works until the thing gets below 7V? Dunno.

I'll see if I can find the little sheet it came with for more details. 

So you're saying it OUTPUTS a square sine wave? I still don't understand how this could be used in a way that the continuity tester couldn't ??


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## 65535 (Feb 18, 2009)

Not a square sine wave a square wave. Two different beasts. At 30Hz a sine wave would sound like a low tone, but a square wave would sound like a vibration.


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## Mr Happy (Feb 18, 2009)

Illum_the_nation said:


> Ask _Mr. Happy_, he'll tell you the details


Mr Happy says: I have not seen this meter before and so I don't know what it can do I'm afraid


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## Russel (Feb 19, 2009)

Looks like a setting to measure pulse width of a pulse width modulated signal.

What does the display show when set to the "Square wave" symbol? Hz? Ms? anything?


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## StarHalo (Feb 19, 2009)

It's a Flux Capacitor waveform meter, do not use above 88 mph..


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## Bonky (Feb 19, 2009)

When the 'square wave form' is selected it just displays a '1'.. 

and I placed the leads on the 3.5mm plug of a pair of headphones and sure enough I hear this weird.. "electrical" sound. Ever unplug a guitar from an amp with the amp still turned on and the amp makes a sort of electrical humming/buzzing sound? This does the same.

Why in the world................ ?


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## Bonky (Feb 19, 2009)

I take it back. It seems to make the buzzing noise on POWERED headphones/speakers, but not on unpowered ones. ?


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## gSPIN (Feb 19, 2009)

Bonky said:


> When the 'square wave form' is selected it just displays a '1'..



its a logic probe function.
short the leads together if it shows a zero.


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## StarHalo (Feb 19, 2009)

Bonky said:


> Ever unplug a guitar from an amp with the amp still turned on and the amp makes a sort of electrical humming/buzzing sound? This does the same.



That would be an AC 60Hz cycle hum, so it probably is some sort of Hz counter.

But I still wouldn't recommend exposing it to anything over 1.21 jiggawatts..


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## Bonky (Feb 19, 2009)

It does not display anything other than '1'.. even with leads shorted or when making powered speakers buzz.


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## FRANKVZ (Feb 19, 2009)

This looks like the same multimeter with a different symbol in that spot: http://cgi.ebay.com/NEW-LCD-HANDY-D...3286.c0.m14&_trkparms=66:2|65:1|39:1|240:1318


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## Bonky (Feb 19, 2009)

yup, that's it all right. They're branded by about a dozen different companies but all are the 'A830L' model.. only thing is, that model is supposed to come with a 1.5V batter tester feature in that spot. Mine comes with ... that weird square wave thing that I can't figure out what it does.

I've searched online and found other DMMs with "square wave output" but nobody has indicated what in the world they would be used for and they're usually adjustable.


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## PeAK (Feb 19, 2009)

Bonky said:


> .
> .
> .
> So you're saying it OUTPUTS a square sine wave? I still don't understand how this could be used in a way that the continuity tester couldn't ??


It's meant to be used as a handy signal generator to help you pinpoint and trace problems gain devices such as power amplifiers.



TakeTheActive said:


> Connect a (disposable / inexpensive / EXPENDABLE) 8 ohm speaker to the meter leads and see if you hear a tone...


An 8 ohm load might be too difficult a load to drive resulting in the normal 2 volt signal becoming very weak and inaudible. I'll make some measurements later to check on my particular unit.



Bonky said:


> When the 'square wave form' is selected it just displays a '1'..
> 
> and I placed the leads on the 3.5mm plug of a pair of headphones and sure enough I hear this weird.. "electrical" sound. Ever unplug a guitar from an amp with the amp still turned on and the amp makes a sort of electrical humming/buzzing sound? This does the same.
> 
> Why in the world................ ?


Headphones are an easier load (especially iPod/MP3 based ones) and can play back the low drive signal from the DMM. The square wave will sound like a PA system with 60Hz buzz clipping the system. In your case, the flat tops of the square waveform are the higher frequency components of the 30 Hz fundamental (i.e. 60, 90, 120 Hz...etc).

Other easy to drive loads, such as powered speakers, will also be able to be heard as they do not collapse the signal level when attached to the DMM leads.

PeAK


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## 65535 (Feb 19, 2009)

what peAk said, that signal is very weak. An 8Ohm speaker is normally rated from about 0.5watts up to a few 100watts. I'm guessing that signal is in the mW range.


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## Bonky (Feb 19, 2009)

ok well I found a sort-of way to use it. If I have powered speakers with tangled cables I can attach the DMM to them and find out which cables go to which speakers.

Kind of an esoteric function, IMHO.


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## Russel (Feb 19, 2009)

I agree with StarHalo, keep it under 88 MPH and never expose it to 1.21 gigawatts of power...especially lightning!

Russ

PS: What ever you do, don't connect it to a flux capacitor!


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## Bonky (Feb 19, 2009)

I think we've reached the limit of this thread's humor potential.

If anybody knows what in the world to do with the "square wave output" function OTHER than powering speakers to determine what wires go where, I'd love to know.

thx for all the replies.


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## Mr Happy (Feb 19, 2009)

As other people have mentioned, a common use for a multimeter is diagnostic tracing in electronic circuits to make sure the expected voltages and signals are appearing at the right points in the circuit. Oftentimes a signal source to inject a known signal at the front of a circuit is invaluable when performing such diagnostics. Expensive signal generators can be purchased, but a freebee in a DMM is a bonus that could come in handy for some.


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## fireguy (Feb 19, 2009)

I tried searching the internet but had little success.

Ftike is an electronics company based in Shenzhen, China. This is a large manufacturing area, and many NiMH battery manufacturers operate in Shenzhen. According to what I can find out, when the display shows "1" it means that it's an "over range error". This makes me think that this mode is actually an input, not an output.

What I could find states "Can be measured AC and DC voltage, AC and DC current, resistance, temperature, battery, diodes, transistors, and circuit-off test, as well as the symbols are used to indicate units." I wonder what the circuit-off test is?

They do mention that the meter is "handsome in design" and that it has "LCD display, with background light even in the darkness like their handy." :laughing:




FTIKE

Digital Multimter A830L

New Digital Voltmeter - DMM Multimeter Ohm Meter 

*
Continuity Beeper - Diode Tester
*
Transister Tester
*
Battery Tester
*
DC Voltage: 200mV /2V/ 20V / 200V / 500V(+-0.5-0.8% + 2-3digits)
*
AC Voltage: 200V / 500V (+-1-1.2% + 10digits)
*
DC Current: 200uA/2mA/ 20mA / 200mA / 10A (+- 1.0-3.0% of rdg + 2digits)
*
Resistance: 200/2K/20K/200K/2M Ohm(+-1.0-1.5% 3digits)
*
Standard Accessories Test Lead, Battery, Manual
*
3.5 digits
*
Max 1,999 Count Display
*
Data Hold
*
Display Backlight
*
Power 9V Battery(6F22 9VOLT)
*
Low Battery Display 

Package includes:

* 1 x Digital Multimeter
* 2 x Test leads
* 1 x 9V alkaline battery 

Dimension: 5 3/4" L x 2 7/8" W x 1 1/2" H

Weight: 7.2 oz (included 9V battery)


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## TakeTheActive (Feb 20, 2009)

I discovered that my 'inexpensive' Craftsman 82015 DMM has the same 'feature', so I dug out the manual and found:

*SIGNAL INJECTION FUNCTION*

This function allows the injection of a square wave, about 2V peak at a frequency of 30 to 40 Hz into an audio device. Use to test an amplifier to see if it is functioning.
Set the function switch to "_that square wave symbol_".
Touch the black test probe tip to the circuit ground.
Touch the red test probe tip to the point in the circuit where you wish to inect the test signal.


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## PeAK (Feb 20, 2009)

65535 said:


> what peAk said, that signal is very weak. An 8Ohm speaker is normally rated from about 0.5watts up to a few 100watts. I'm guessing that signal is in the mW range.



I loaded down output and calculated an output resistance of 185 kilo-ohms. When you use a load of 200 kohm, the square wave signal drops to about one half the unloaded value at 1V peak. This means the maximum power is at most 5 microwatts. Into a standard 47kohm input (like the DVD input of a receiver), that peak output would be 400mV...just about the right level to be used as a signal generator.

PeAK


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## fireguy (Feb 20, 2009)

TakeTheActive said:


> I discovered that my 'inexpensive' Craftsman 82015 DMM has the same 'feature', so I dug out the manual and found:
> 
> *SIGNAL INJECTION FUNCTION*
> 
> ...


Well, you certainly nailed that one on the head! Good job!


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## Turbo DV8 (Feb 21, 2009)

Bonky said:


> I think we've reached the limit of this thread's humor potential.


 


> I agree with StarHalo, keep it under 88 MPH...
> Russ


 

It's a "Rough Road Ahead" warning...


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## SilverFox (Feb 22, 2009)

Hello Turbo DV8,

Is that like a warning for Speed Bumps...  

Tom


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## EngrPaul (Feb 22, 2009)

I feel jeallous. I don't have that setting on mine, but is otherwise similar.

*Is yours set up for "LANDSCAPE" mode? I never saw a power button that looks like* 

"Θ"


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## PhotonWrangler (Feb 22, 2009)

Russel said:


> I agree with StarHalo, keep it under 88 MPH and never expose it to 1.21 gigawatts of power...especially lightning!
> 
> Russ



At least not until you fix that (thump, thump) intermittent time circuit.


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## Turbo DV8 (Feb 22, 2009)

Well, if it's truly a "multi" meter, with multiple uses, maybe if you set it to that setting and begin to knit with the probe tips, that is the resultant stitch pattern you will get.


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