Cen-Tech Multimeter from Harbor Freight

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Brozilla

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Just bought this last night for $2.99 in store. Now when I try to test for resistance, when I put both test pins together, Im getting whole lotta numbers jumping up and down, first multimeter I've used ever so I need help using it, I followed the instructions on the package but I cant get it down. Anybody own this particular one and give me some help

http://www.harborfreight.com/7-function-multimeter-98025.html
 

Rickajho

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I could just be poo.

Test leads into the two bottom holes. Set the meter on 200 ohms. (should be about 12:00 position.) When you turn it on the display should read a single digit "1". Touch the leads together and if it's properly zeroing it should read "0".

If the display is jumping around all over the place - before or after you touch the leads together - you just found out why it's a $2.99 meter. Take it back and test the next one before you leave the parking lot.
 

spider362

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Also be aware that these meters do not have a zero adjust so when you touch the leads together you will get some reading other than zero.

  • Before you do a resistance test, touch the leads together and write down the reading you get.
  • Then make the test.
  • Subtract the first reading from the second and you'll have the actual resistance of the device you are testing.
 

westy78

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I have a cen-tech multimeter from HF and got curious tonight and tested my "2.4 ohm" atomizer heads in various states of gunkiness. I'm getting readings anywhere from 3.6 to 5.6 ohms depending on the head (one unused one read 7.0--don't know what's up with that). But then again when I touch the leads, it tells me 1.2 ohms! Guess its time to pick up a better meter and leave this one to voltage testing when wiring outlets.

BTW, when I test my twists, the meter consistently shows 0.2v higher than the twist markings. Don't know whether the batts or the meter is wrong. Will post again after I pick up a new meter.
 

c00lkatz

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Touch the two leads together, record reading, take one lead out, touch remaining lead where the other lead plugged in, record reading. If the reading halves, then you're measuring lead resistance. If the reading remains the same, then you've got some internal resistance of the meter. Either way, you should only read around 0.3 or so when touching the leads together. Something as high as 1 ohm I wouldn't even use. If the above test comes up lead resistance, then I'd try a new set of leads before tossing the meter.

Also, I've found with using any meter that using the tips of the leads will result in weird and wandering readings. Use the flat part of the lead, and you will get much more stable readings. You will still see some fluctuation but it will be very minor. Make sure you subtract your internal/lead resistance (as described above, touch the leads together and record that resistance) from your final resistance readings to get actual resistance.
 
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Brozilla

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Touch the two leads together, record reading, take one lead out, touch remaining lead where the other lead plugged in, record reading. If the reading halves, then you're measuring lead resistance. If the reading remains the same, then you've got some internal resistance of the meter. Either way, you should only read around 0.3 or so when touching the leads together. Something as high as 1 ohm I wouldn't even use. If the above test comes up lead resistance, then I'd try a new set of leads before tossing the meter.

Also, I've found with using any meter that using the tips of the leads will result in weird and wandering readings. Use the flat part of the lead, and you will get much more stable readings. You will still see some fluctuation but it will be very minor. Make sure you subtract your internal/lead resistance (as described above, touch the leads together and record that resistance) from your final resistance readings to get actual resistance.

I'll try that tonight! thanks alot
 

veganvap

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I read if you turn the selector dial a full turn, it fixes it.
That didn't fix it. It still jumped from hundreds to negatives while trying to get the lead-to-lead # to subtract from the coil reading. It also jumped from hundreds to negatives when trying to read the coil resistance.

I spun the dial like 3 times with the multimeter on, and stopped it at 200 ohms to check the coil.
That didn't fix it, and I got the same jumping #'s result.

I took a lighter to the leads, heated them up and then wiped them clean while they were hot, hoping it would remove any manufacturing resides and/or somehow make the metal more conductive.
That sort of fixed it for a short time.
I got the lead-to-lead resistance to stay at 1.0, and then a brand new unused 1.8 kanger T3 head read 3.0, so either the coil's really 2.0 ohm or the meter's off by .2.

I bought one for myself and another for someone else, and this temporarily fixed both, but now they're back to jumping all over, so I'm returning them.
There are many different brands on the net that are the same design as this, just with different colors, so I'm staying away from those too.

Sometimes HF gives these away free with any purchase, what a great busines strategy to hand out defected items, but really, I think most consumers are using these to read volts of things like batteries and outlets, so no-one really complains. I read that volts are more accurate than testing resistance (ohms), so unlike the problems reading resistance ohms, it should at least accurately read PV battery volts.

It's not worth guessing if the reading's right if you don't have a stock-built/known- resistance coil to use as a referance. You're better off asking the forum what ohm = how many # of wraps with the gauge wire you're using.
 
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WillyB

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... It's not worth guessing if the reading's right if you don't have a stock-built/known- resistance coil to use as a referance. You're better off asking the forum what ohm = how many # of wraps with the gauge wire you're using.
No your not, unless of course they and you own a Digital Caliper so you can also duplicate the wick/coil diameter exactly.


I got the lead-to-lead resistance to stay at 1.0, and then a brand new unused 1.8 kanger T3 head read 3.0, so either the coil's really 2.0 ohm or the meter's off by .2.
Rarely do these coils ohm out exactly as claimed.


@ the OP

I've got the exact one you linked to (they make 3). Although it's no consolation mine has worked fine for years now. The ohms do take a while to settle down to .7Ω naked, but it reads a 2Ω surplus 1% wirewound resistor correctly (subtracting .7 off course). I tend to use another meter for ohms though. I keep the HF set on volts and like the convenience of the on/off switch for quick tests. I'm glad I got it.

You may want to try polishing the banana plugs (that plug into the meter) with a little steel wool and maybe try a new battery if you have one on hand.

Extech makes decent meters (I have a MN15A). This one looks good.

Amazon.com: Extech MN35 Digital Mini MultiMeter: $19.04

Very nice display, higher end leads and you can do temps too. Do note to get a more accurate meter you would have to spend nearly 4X more.
 

spider362

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I finally got tired of mutzing around with the $2.00 Harbor Freight Multimeters and decided to go with the best auto-ranging one they had.

Settled on the 14 Function Professional Digital Multimeter from Cen-Tech.

Normally it's $45 but I had a 20% off coupon (which you can get off their website) bringing it to $36.

It has a few usless features (for vapers, anyway) like db (sound level) and lux (luminosity), but a couple nice features are a remote temperature sensing probe and Relative (when checking resistance you can touch the leads together and then press the REL button to zero the meter. You will then get the actual resistance of the device you are checking).

It's both Auto and Manual ranging at the push of a button.

Back light is white and bright.

It's a little large to just carry around in your pocket, but otherwise it seems to be a very decent meter for the price.

If you would like to see the manual, click on the "Product Manual" tab in the above link to download the PDF file.

EDIT: It doesn't show on the image of the probes below, but they come with little tip protectors that will insulate the sides of the metal probe and just leave the tips exposed.

Here's what you get:

5-in-1 Digital Multimeter.jpg5-in-1 Digital Multimeter Probes.jpg
 
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Thepinfamily

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The Harbor freight I go to throws one in my bag for free on sale days or if I spend a certain amount. I had 5 still in the package. I have used a meter just about everyday for the last 20 years. Both work and hobbies at home require it.
One day a few weeks ago I left my meter in the car. It was cold and I didn't feel like walking outside. It would have required me to put pants on. I was just checking some diodes and transistors. I decided to open one of the 5 meters the OP linked. It didn't work. I checked several functions and none of them worked. Just numbers bouncing around. I opened all of them one by one and out of 5 one worked. I even took two of them apart trying to see what the problem was but never found it. Then I thought "well at least I have 5 sets of leads". Nope, the leads don't fit my meter. I tossed them all in the trash. Even the working one. I can't trust it. I need to be able to trust my meter, sometimes its life or death. Power can kill you.
 
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DaveP

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The little meters from Harbor Freight are sufficient if you can work the resistance out of the contacts. Turn the dial round and round a few times to wipe the rotary contacts (as described in an earlier post). That cleans the solder tinned contacts to give you a more accurate reading. The leads will also have a certain amount of resistance, also. Mine read 4 ohms pretty constantly. You have to plug and unplug them to wipe the socket contacts. Touch the leads together and wait a few seconds for the reading to stabilize. The reading you get is called "lead resistance". Deduct that reading from whatever you read on your atomizer coil. Better meters zero themselves when you do that and maintain the reading at zero if you do it every time when you begin to use it.

I have a stack of those meters around the house, in the basement, and in my truck. They are handy for simple readings.

Or, you can spend over $100 and buy a good meter that auto-zeroes and calibrates itself. The cheap meters are good for reading battery voltages and checking resistance once you understand their limitations.

I used Weston, Simpson, and Fluke meters throughout my career as a field engineer. I still have a Simpson Digital at home with a work sticker on it. They didn't ask for them back when they passed out the Fluke 87's. :)

Check out Google for "Best digital multimeters under $100" and you will probably find something that is more user friendly once you read the reviews. It's a purchase that you can use the rest of your life and only costs about as much as a middle to upper level ecig mod. You want a meter you can trust.

You can start here for a reference point and reviews from demanding users. Those flashlight guys are sticklers about quality!
http://www.candlepowerforums.com/vb/showthread.php?215683-Best-multimeter-Other-tools
 
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ngeepro15

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I work in a window manufacturing plant as a maintenance technician and the only meter I will use is a Fluke. There ate other brands that ate cheaper but i deal with high voltage sometimes and im not putting my life in the hands of a cheap meter.

When it comes to tools there is a good saying to follow: "You get what you pay for". This applies to all tools. If the tool is cheap then it was made cheap and most likely wont last long at all. We have another name here at work for these cheap tools, which is "Trinity Tools" due to the fact that they eventually will send you to the Trinity Hospital.

If you want a good tool/meter then Harbor Freight is the last place you would step foot into. In my opinion Granger is the best place to go for quality tools at a great price and there is one just about everywhere. I have never been to a Harbor Freight myself and never plan on doing so.

Always remember though, from screwdrivers to multimeters, you get what you pay for. Like someone said, there is a reason Harbor Freight just gives those things out.
 
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