What's the difference between continuity and resistance setting for connection? - Page 1
Forum section: electronics / beginners

author: geratheg
author_rank: Regular Contributor
timestamp: August 05, 2014, 05:13:49 am
content: If I want to see if there is direct contact in a connection, what's the difference between the resistance setting and the continuity setting on the multimeter? Won't both show whether there is a connection?The resistor setting would just show near 0 resistance.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: August 05, 2014, 05:22:38 am
content: May depend on the meter but I'd hazard a guess and say that 99% of meters will show resistance in continuity mode, the only difference is the audible beep in continuity mode

author: sleemanj
author_rank: Super Contributor
timestamp: August 05, 2014, 05:34:11 am
content: Continuity will typicallybeeplock into a low resistance testing mode if normal resistance autorangesit's possible it uses a different test voltage (eg if continuity was shared with diode testing)maybe other stuff depending on meter

author: geratheg
author_rank: Regular Contributor
timestamp: August 05, 2014, 05:36:47 am
content: My meter doesn't beep on continuity mode, but does show resistance.I guess it's the same as the low resistance setting on my meter.Thanks for the replies.

author: tautech
author_rank: Super Contributor
timestamp: August 05, 2014, 05:47:19 am
content: Normally a DMM with continuity beep has a resistance threshold of less than ~50 Ohms for it to beep.They also generally display the resistance at the same time.There is no point of having a DMM Continuity setting if it does not beep.Maybe yours is broke!

author: ejeffrey
author_rank: Super Contributor
timestamp: August 05, 2014, 07:02:43 am
content: Some meters also have an option to turn the beep off. Normally this is due to "features" where the meter makes obnoxious beeps when you turn it on or change the range switch. When you turn off the annoying useless beeps, it sometimes turns off the useful continuity beeper.

author: jmoreland79
author_rank: Regular Contributor
timestamp: August 05, 2014, 01:30:55 pm
content: The main advantage for continuity mode is that it can detect a short (or whatever the specified range is) almost instantly where measuring resistance can take a few seconds for the reading to settle.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 05, 2014, 02:15:39 pm
content: Having been brought up on analog meters,I very seldom use the continuity function.I like to know if I have a real connection,not,say,50 Ohms!My Fluke 77 resistance reading settles down quite fast----considerably faster than most of the modern cheap DMMs I've tried.

author: xwarp
author_rank: Frequent Contributor
timestamp: August 06, 2014, 12:13:32 am
content: https://www.eevblog.com/forum/reviews/fluke-87-v-continuity-beeper/

author: robrenz
author_rank: Super Contributor
timestamp: August 06, 2014, 12:31:50 am
content: Some meters have an adjustable threshold for continuity. The 8846A has 1, 10, 100, or 1000 Ohm thresholds for a continuity beep.

author: ejeffrey
author_rank: Super Contributor
timestamp: August 06, 2014, 05:04:58 am
content: Quote from: jmoreland79 on August 05, 2014, 01:30:55 pmWatch out, this is only true on some meters. Ideally, a meter would have a dedicated comparator (even better: latched) for the beeper. However, some meters have very slow response, presumably because the continuity detector is a software-only feature that uses the main ADC with its very slow settling time, and possibly additional latency on top of that. These software modes don't deserve to be called a continuity detector. They are worse than useless: they tempt you to use them and then mislead you because they don't beep before you have moved the probe. A lot of them have latency on the order of 500 msec! You can fly to the moon in 500 milliseconds. You can fly to the moon in 500 msec! (actually the moon is 1.3 light seconds away...)@vk6zgo: a good continuity beeper is better than any analog meter. You can slide a probe across a row of pins or pads and detect if any of them are shorted to common without having to even look at the display. Once you find the pin, you can hold the probe and look at the reading to see if it is 30 ohm or 1 ohm. You can sort of do this with an analog meter since they are so much faster than their digital brethren, so even momentary contact is often enough to deflect the needle at least part way, but you still have to look, and a dedicated digital comparator is faster than an analog movement.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 06, 2014, 07:05:52 am
content: It that's all you want to do,you can do it with an analog beeper,which is even faster!The problem with continuity tests is that they will beep whether they are seeing a short which may be abnormal,or a low resistance,which may not.