Can't Resistance Show The Same As Continuity? - Electrical - DIY Chatroom Home Improvement Forum

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12-18-2011, 09:10 AM   #1
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## Can't resistance show the same as continuity?

Confused- yes, resistance indicates ohms in a circuit, and it helps to know what the value is, but is a continuity test also able to show the same thing? I mean, how does continuity show up if it doesnt use resistance to "tell" the multi meter?

In other words, if you get infinity for ohms, that right there must show no continuity, right?

Thanks

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12-18-2011, 09:33 AM   #2
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Yes, that is correct. Assuming, of course, that you have the multimeter set on the proper scale.

Even a dead short has some resistance, but far too little for the typical instrument to measure.

Last edited by md2lgyk; 12-18-2011 at 09:36 AM.

 12-18-2011, 11:34 AM #3 Idiot Emeritus   Join Date: Mar 2008 Location: Fernley, Nevada (near Reno) Posts: 1,849 Rewards Points: 1,492 It depends on your definition of continuity. It could be said that any electrical load (even a short circuit) has continuity, but they all have resistance as well. Generally speaking, continuity indicates whether or not current will flow in a circuit. Resistance indicates how much current will flow.
 12-18-2011, 04:46 PM #4 Semi-Pro Electro-Geek   Join Date: Jul 2009 Location: Arizona, USA Posts: 2,976 Rewards Points: 2,852 A "continuity tester" is just a low-accuracy resistance meter with no numerical readout, and a "good/bad" indicator instead. Usually if the resistance is below several tens of ohms, it shows continuity. You can use an ohm meter instead of a continuity tester for any purpose. You can only sometimes substitute a continuity tester for an ohm meter.
 12-18-2011, 05:32 PM #5 Member     Join Date: Jan 2008 Location: Long Island Posts: 3,630 Rewards Points: 2,000 putting the leads together is a dead short and continuity as the meter goes to 1.0 leads seperated 0.00 infinity the resistance is between there...reading coils and having different settings 20,000 200,000 gives your range to see resistane thru the coil.as a residence in a coil gets weaker say in a coil for a relay it is getting closer to becoming a dead short on a 24v circuit and blowning a control fuse.... __________________ http://www.youtube.com/watch?v=U1qEZHhJubY
 12-18-2011, 05:36 PM #6 I=E/R     Join Date: May 2010 Location: Minnesota Posts: 2,052 Rewards Points: 1,000 The two extremes of a circuit are Open and Short. Open is indicted on a meter as Infinite Ohms and a Short is indicated as Zero ohms. When talking continuity we are, in most cases, referring to a wire that does not have a break. Your multimeter, whether digital or analog, has a battery that will actually create current flow when you have the meter set to measure resistance and connected to a circuit. The display will indicate the equivalent resistance in ohms. With the meter set to measure resistance and the leads not touching anything, the display will indicate infinite resistance and when the leads are touched together the display will indicate zero ohms. When using a meter to measure resistance the circuit must be dead - no power. When testing for continuity we are looking for an very low resistance. Wire, whether copper or aluminum, has resistance which increases as the length of the wire increases.
12-18-2011, 06:44 PM   #7
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Quote:
 Originally Posted by noquacks Confused- yes, resistance indicates ohms in a circuit, and it helps to know what the value is, but is a continuity test also able to show the same thing? I mean, how does continuity show up if it doesnt use resistance to "tell" the multi meter? In other words, if you get infinity for ohms, that right there must show no continuity, right? Thanks
Contiuity is not supposed to be expressed in terms of ohms,
All contiuity means is there is a complete circuit or not !
So they might be used together,
but they are technically different things.

 12-18-2011, 08:02 PM #8 Member   Join Date: Jun 2010 Location: se Posts: 1,597 Rewards Points: 1,062 Thnaks guys. Good education. So, I guess I dont neccessarily need to but a meter with a continuity function, eh? I still understand continuity as an almost useless value/function (if it is used to show ANY ability to transmit voltage, when in fact it may even be way inadequate if the wire is faulty and not able to maintain the right resistance/load). One ideally needs to know the resistivity range and measure, and if its out of range, the wire/circuit is bad, period. (right?) I need to study this more. __________________ Alexander Pope: [a little knowledge can be a dangerous thing]
 12-18-2011, 08:30 PM #9 I=E/R     Join Date: May 2010 Location: Minnesota Posts: 2,052 Rewards Points: 1,000 I think you are making too much out this. Continuity is a condition not a measurement. A wire either has or does not have continuity. In fact something like a light switch also has continuity when in the ON position. A fuse also has continuity if it isn't blown. If you are troubleshooting a problem you may have to test for continuity in which case you will need something to do the test with.
 The Following User Says Thank You to a7ecorsair For This Useful Post: micromind (12-18-2011)
 12-18-2011, 10:00 PM #10 Member   Join Date: Dec 2010 Location: southeastern mass. Posts: 243 Rewards Points: 16 from a practical point of view, all that has been said in this post is true. If memory serves me from 40 years ago, conductance (continuity) is the inverse of resistance. the unit of conductance is the mho (note ohm backwards) reminds me of abbott and costello "who is on first" enjoy.
12-18-2011, 10:31 PM   #11
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Quote:
 Originally Posted by bernie963 from a practical point of view, all that has been said in this post is true. If memory serves me from 40 years ago, conductance (continuity) is the inverse of resistance. the unit of conductance is the mho (note ohm backwards) reminds me of abbott and costello "who is on first" enjoy.
Your memory is fine but conductance and continuity are not interchangeable terms.

12-19-2011, 04:33 AM   #12
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Quote:
 Originally Posted by bernie963 from a practical point of view, all that has been said in this post is true. If memory serves me from 40 years ago, conductance (continuity) is the inverse of resistance. the unit of conductance is the mho (note ohm backwards) reminds me of abbott and costello "who is on first" enjoy.
If he cannot yet get his head around contiuity.
Then he has no chance with conductance !

12-19-2011, 12:19 PM   #13
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Quote:
 Originally Posted by noquacks I need to study this more.

An understatement if there ever was one.

 12-24-2011, 09:32 AM #14 Member   Join Date: Jun 2010 Location: se Posts: 1,597 Rewards Points: 1,062 Sorry for late reply, people (too much christmas shopping). Thnaks for the continued feedback. I think I get it. Now, for a good meter, what specs do I look for with good capabilities for very low reststivity measurements? Also, I guess I will look for the continuity function....... I dont want to just buy another \$9.99 HF one. (last one showed faulty ohms and I almost dumped out a perfectly good ac compressor coil cuz of that!!) __________________ Alexander Pope: [a little knowledge can be a dangerous thing]
12-24-2011, 09:51 AM   #15
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The continuity function is a nice feature and creates a beep so you don't have to be looking at the meter. It beeps at some preset low resistance.
Plan to spend around \$40 for something at HD or Lowes or Sears or go all out and get a Fluke.

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