Why do we want fast continuity detection in a multimeter? - Page 1
Forum section: electronics / testgear

author: Hogwild
author_rank: Regular Contributor
timestamp: June 04, 2023, 05:14:41 am
content: Hi everyone:Let's assume I'm a complete newbie, with next to no understanding of electronics and only basic knowledge of how to use a multimeter.In many of the Dave's reviews, we watch him check the continuity test function of a meter by shorting the two leads and listening for how quickly the meter beeps. Faster is better, apparently.Please help the newbie understand, why do we want faster speed doing this? Will a fraction of a second make a difference? If a meter responds slowly, is that a sign of other issues which might occur, or just poor build quality? Since continuity is the inverse of resistance, I wonder if it's a sign the meter will be innacurate with resistance tests.I ask because I just got a Zotek ZT-Y. It seems to match the other meter I use so far for measurements, but doing that continuity test, it's definitely quite a bit slower.

author: ataradov
author_rank: Super Contributor
timestamp: June 04, 2023, 05:25:00 am
content: It is not about being faster, it is about latching the first continuity reading and producing a sound for a bit even if there is no longer continuity there. This eliminates the scratchy sound because of contact bounce.A good meter should be imperceptibly fast, if it is slow enough to be noticeable, then it will annoy you all the time. And you will potentially be missing continuity when doing a lot of measurements (like tracing a board or a cable harness).

author: Hogwild
author_rank: Regular Contributor
timestamp: June 04, 2023, 05:29:34 am
content: Hmm..yeah, that's sort of what I figured.So, I think I may have jumped on the ZT-Y too quickly. Are there models higher up in the same line, with the same or similar LED display? I have trouble with my eyes, and very little lighting in my place. That combination made the ZT-Y very appealing to me. And I do love the display, but I'm wondering if there's something of better quality in the same line with similar great display.

author: ataradov
author_rank: Super Contributor
timestamp: June 04, 2023, 05:56:25 am
content: No idea about LED displays, but one way around this may be to use another meter for continuity, since it does not require looking at a display. Not ideal, but it is hard to guess with all the random cheap meters.

author: DaJMasta
author_rank: Super Contributor
timestamp: June 04, 2023, 05:57:15 am
content: Try using a continuity tester to buzz out traces on a board. If it's fast, you can use one probe on the thing you're trying to find the route to and just brush the other probe on contacts as you need - along the pins of a SOP package, for example - and just hear a little noise if it makes contact.If your continuity tester is slow, you have to try every individual pin because you need to wait to see if it sounds. A slow continuity tester isn't just on a delay, it's actually taking that delay worth of time to decide if the continuity is there (basically just looking for a resistance measurement below a certain threshold), so if it's slower and you drag it across pins with only one actually connected to the other point, you may miss it entirely because the time the probe is on that one pin is pretty small.Latching is a nice QoL feature, but is very much the secondary feature to me - I want it to tell me quickly so I can cover a lot of potential pins in a short amount of time.

author: HKJ
author_rank: Super Contributor
timestamp: June 04, 2023, 06:06:32 am
content: Fast continuity is very useful when tracing connections.You canslideone probe across IC or connector pins and if any of them are connected to the place where the other probe is, the buzzer will sound. With a slow continuity you cannot do that, but have to check each pin individually and that is MUCH slower.

author: Aldo22
author_rank: Super Contributor
timestamp: June 04, 2023, 07:00:58 am
content: Reasonable speed in continuity testing does not necessarily have to be expensive.For example UNI-T UT123https://youtu.be/s8mRZVx4m6k?t=607These are also available under the nameVOLTCRAFT VC-22(only in Europe?)

author: Fungus
author_rank: Super Contributor
timestamp: June 04, 2023, 07:44:32 am
content: It's like playing a piano. When you press a piano key you want a soundNOW, not in half a second.No, it's not indicative of other problems.

author: kripton2035
author_rank: Super Contributor
timestamp: June 04, 2023, 07:47:04 am
content: you can even build one yourself , and it can even detect where a short is on a board ...http://kripton2035.free.fr/Projects/shorty-display.htmlhttps://youtu.be/8mYyr9uKpFU

author: nctnico
author_rank: Super Contributor
timestamp: June 04, 2023, 10:56:53 am
content: Quote from: DaJMasta on June 04, 2023, 05:57:15 amIMHO latching is just as bad as a delayI like the raw information (even if that means intermittent sound) because it tells me how well the probes make contact. For measurements where I want to be sure there is continuity or not, I do 3 measurements: A-A A-B and B-B while holding one probe in the same spot. That way I also know whether the probe actually made contact during the measurement.

author: Hogwild
author_rank: Regular Contributor
timestamp: June 04, 2023, 06:06:19 pm
content: That's a ton of useful information. Thanks. So, does anyone know whether any Zotek/Zoyi models higher in the product line have better continuity testing?

author: Fungus
author_rank: Super Contributor
timestamp: June 04, 2023, 07:36:54 pm
content: I don't think the ZT-Y will be a slow meter.The probes make a big difference. Try cleaning the points with alcohol or soap to remove grease, see what happens.Next: Get some gold plated probes.

author: TimFox
author_rank: Super Contributor
timestamp: June 04, 2023, 07:47:01 pm
content: Building on comments above:Moving a probe along a metal trace or wire often gives an intermittent connection, depending on the state of the probe (Au plating is better) and the junk on the surface of the wire (especially solder flux and oxidation).

author: BeBuLamar
author_rank: Super Contributor
timestamp: June 04, 2023, 07:53:08 pm
content: I use the resistance measurement to check for continuity normally. It would tell me how good the continuilty is. I use the contnuity function when it's intermittent and it happens to quick to take a reading.

author: Hogwild
author_rank: Regular Contributor
timestamp: June 04, 2023, 09:12:13 pm
content: The Pomona probes I have work very quickly with my old Mastercraft meter. They work much more slowly when connected to the Zotek. That tells me it's not the probes.

author: bdunham7
author_rank: Super Contributor
timestamp: June 04, 2023, 09:41:29 pm
content: Quote from: Hogwild on June 04, 2023, 05:14:41 amThe continuity beeper response and the resistance ranges aren't related like that and continuity ranges typically display in ohms, although some might not. Typically people want fast continuity so they can quickly scan a row of contacts instead of slowly poking at them. Although there are some cases where latching is a detriment, the ideal continuity feature pack (IMO) is fast, latching (with a short signal just long enough to be definitely heard), fast bargraph action and an ohms display with multiple ranges and multiple continuity thresholds.Not having 'good' continuity features usually doesn't say much about the meter in general or how it might perform in other ranges. I suppose you might think that a meter that does everything slowly might also be slow with continuity, but not always. The Fluke 289, for example, is pretty slow to autorange in ohms and to settle in the low-ohms range but has lightning fast continuity as well as all of the features I mentioned. A lot of these issues are design choices rather than straight up good-or-bad design.

author: Martin72
author_rank: Super Contributor
timestamp: June 04, 2023, 09:41:52 pm
content: Continuity tests...We do this nearly every day when checking the point to point connections of wired cabinets for example.Each wire got it´s own number in the schematic and on itself, so we first check the connection on the schematic and then "beep out" the connection in the cabinet/circuit.This takes time...So for our purposes it is not important how fast a tester react.Mostly we turn off the beeper (and watching the display instead)because if you test a cabinet it could last 1..2hours or more and then the sound could be very annoying.PLUS: There is a kind of threshold when the meter will beep - Most of the meters will beep under a specified resistance value.Not when the connection is "zero" ohms.So if you got lower value resistance connections in the circuit and test the connection only via beep, you won´t know if this connection is right.

author: mwb1100
author_rank: Frequent Contributor
timestamp: June 04, 2023, 09:43:25 pm
content: As far as other Zotek meters, I have a ZT-301 that has a perfectly fine continuity buzzer. It doesn't have the same kind of display as the ZT-Y, but the ZT-301 has a backlight that stays on for 15 minutes (essentially, the ZT-Y's display is backlit all the time which is one of the things that gives it a highly readable display).Also keep in mind that many (most?) Aneng meters are Zotek rebrands, so you can get an idea of the continuity performance from the hundreds of reviews of Aneng's various meters on the web. I believe all of the hugely popular Aneng AN8000 series are Zotek built.Another thing to consider is keeping the ZT-Y that you like and getting a cheap second meter for times when you need/want the quick continuity (note that even though the ZT-Y doesn't seem have top-of-class continuity speed, it's not too bad in my opinion). Plus then you have a second meter for whatever (a go bag, to be able to do current on one and voltage on another, etc.). A super cheap meter that has instantaneous continuity buzzer:-Mastifuyi FY77which is less than $10 right now on Amazon US (with a coupon you have to select)Keep in mind that I generally replace my cheap meter's probes with something better - you might need to do the same with the FY77 - I don't remember if the probes that came with it had delayed continuityAlso, don't use something like the FY77 on mains - keep it to low voltage electronics.

author: Brumby
author_rank: Unknown
timestamp: June 05, 2023, 01:42:18 am
content: You want fast detection and only enough latching for you to hear a beep.This is most helpful in the situations where you are testing a lot of points.For example:Quote from: HKJ on June 04, 2023, 06:06:32 amIf you swipe along 20 contacts in half a second, you will want fast response so that you don't miss any hits. It's really useless if you actually have continuity and the meter is so slow that it didn't have time to tell you before you moved on!As for latching - you only need that to be long enough so that you hear the beep.Certainly, when "sliding" your probe may have moved on from the target connection by the time the meter soundsand you respond(don't forget that) but once alerted, you go back and double-check the last few points to positively determine the winner. It's at this stage you can check the actual ohms.This is the process I use in my efforts as a hobbyist and (from my observation) so do a great many. Nevertheless, there will be those that do continuity testing at the professional level that will have developed a finer sense and more polished processes with more specific requirements that may be necessary for particular situations, but the above is certainly adequate for common usage - IMO.I find Dave's test for speed and latching on a meterveryuseful.

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2023, 04:15:53 am
content: Quote from: Brumby on June 05, 2023, 01:42:18 amI don't recall ever doing that so it wouldn't be something I'd lose sleep over, but...Quote from: Hogwild on June 04, 2023, 09:12:13 pmQuote from: Hogwild on June 04, 2023, 09:12:13 pmI don't have that exact model Zotek so I can't really comment but none of the ones I have areunusablyslow.Whatever: If you ever find yourself zipping down long rows of pins you can use your Mastercraft.There's no such thing as a perfect meter. Everybody here owns dozens of meters and has a favorite for each job.

author: floobydust
author_rank: Super Contributor
timestamp: June 05, 2023, 04:22:59 am
content: I use older DMM's that use an analog comparator (no MCU involved) for the continuity detect.This gives lightning fast response which is invaluable if you are looking for a bad connection. Wiggling things you can "hear" the scratching sound of the bad connection and find it FAST. Is it the cable, the connector, the switch etc., you can find right away.Not so with these sluggish MCU-involved DMM's.

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2023, 04:26:02 am
content: Quote from: floobydust on June 05, 2023, 04:22:59 amYep. People often complain about the "bad sound" of the scratchy ones sound but they give more info.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: June 05, 2023, 05:05:00 am
content: I agree with the many prior posts that say that fast is good. I have seen no specific statements about how fast is good enough. I am sure that everyone's opinion on this will vary, but to give the OP something to work with I will mention what I think the numbers should be.Human reaction time to a sound or other stimulus is a few hundred milliseconds, with many variable involved. So times faster than two or three hundred milliseconds are probably not discernable by everyone, and not of major benefit to anyone. The possible exception to this is the sweeping over a connector example, where a faster time would allow you to more quickly determine that a pin somewhere in the connector was connected. But even in this case a slower, human limited scan would be needed to find the specific pin. Maybe a half interval search would still benefit from the faster time, but that isn't an approach that many will use.I have become very impatient with a couple of meters that I have owned that have reaction times in the one or two second or longer time frame. To the point that those meters are no longer in the active stable. So response times under a second are desirable.I will also point out that those who don't prefer to use a beeper for continuity and just watch the meter are forced to be relatively slow and methodical because it isn't possible for most people to place a probe and watch the meter at the same time. In many situations it is difficult to place the probe (and keep it from touching things it shouldn't) without watching continuously. The beep is invaluable in these situations.

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2023, 07:14:33 am
content: Quote from: CatalinaWOW on June 05, 2023, 05:05:00 amIt's very subjective and will depend on what you use your meter for.eg. I already said I never find myself zipping down connectors. I guess the people who "zip" are trying to figure out unknown PCBs which is something I never really do. I mostly build my own stuff so 99% of the time I know where the probes are supposed to go, I'm just checking for bad connections and/or short circuits.I own very fast meters but I wouldn't say it's life or death for me.

author: BeBuLamar
author_rank: Super Contributor
timestamp: June 05, 2023, 11:53:04 am
content: Quote from: Fungus on June 05, 2023, 07:14:33 amI actually rarely ever used the continuity feature. I almost always use the resistance measuring function. But sometimes I use the continuity to troubleshoot an intermittent connection and when it breaks it breaks very briefly.

author: nctnico
author_rank: Super Contributor
timestamp: June 05, 2023, 11:58:08 am
content: Quote from: CatalinaWOW on June 05, 2023, 05:05:00 amFor swiping pins you basically need less than 1 millisecond response time. Even a 1 millisecond pulse to a buzzer will produce an audible 'click' and that is what is needed when swiping pins.

author: Hogwild
author_rank: Regular Contributor
timestamp: June 12, 2023, 03:15:41 am
content: So, if no one knows whether Zotek has a meter with similar display but better continuity testing...BTW, can someone please remind me that abbreviation they use for that type of display?Can anyone tell me if there's another brand of meter with that type of display that has speedier continuity testing? I'd prefer something about $USD 70.00 or less.

author: ataradov
author_rank: Super Contributor
timestamp: June 12, 2023, 03:35:59 am
content: It is hard to find non photoshopped picture, but from what I can tell it is a simple inverted LCD with backlight. The inversion does not really add anything, and it is a gimmick mostly used by cheap meter to appear "cool". This is why there are no opinions on them - nobody can buy and try all that junk.Backlight is the useful part here, it does make display more readable. And if you just focus on finding a good meter with backlight, it is likely to work for you.

author: Hogwild
author_rank: Regular Contributor
timestamp: June 12, 2023, 03:58:47 am
content: I saw this meter beside others that had strong backlights. It was not even close. As I said earlier upthread, I'm a bit of an unusual use case, as I have some vision loss due to disease.

author: ataradov
author_rank: Super Contributor
timestamp: June 12, 2023, 04:05:48 am
content: Well, they may have cranked up the backlight. Backlight is often a weak point, since it is the primary power drain. The type of display is still inverted LCD with backlight. Whether another meter exists with backlight that strong - hard to tell.

author: floobydust
author_rank: Super Contributor
timestamp: June 12, 2023, 04:07:14 am
content: It's called "negative contrast" and pretty sure it's transreflective, meaning it needs a backlight but can sorta work with ambient lighting. I have a Mestek like that and I like it because the display glows and has much better readability than the usual LCD.If you want superfast continuity checking, go analog, go audible.There are no speed standards for multimeters other than watching a youtube review and speculation.A proper test would involve switching on/off a resistance and measuring response time at the beeper.Most DMM's clunk along auto-ranging which is the biggest time hog. Then the filtering and beep threshold time is there too.

author: Fungus
author_rank: Super Contributor
timestamp: June 12, 2023, 04:55:21 am
content: Quote from: Hogwild on June 12, 2023, 03:15:41 amI'm not sure what the problem is. The meter certainly doesn't look slow in this video:https://youtu.be/QYLISmyvlis?t=692

author: HKJ
author_rank: Super Contributor
timestamp: June 12, 2023, 07:38:22 am
content: Quote from: nctnico on June 05, 2023, 11:58:08 amThat depends on how fast you sweep, it can work with 10ms (That is 100 pins a second, but in praxis you will have to do it slower), but 100ms is too slow in my opinion.

author: nctnico
author_rank: Super Contributor
timestamp: June 12, 2023, 08:36:43 am
content: Quote from: HKJ on June 12, 2023, 07:38:22 amNo. Because the time the contact is actually made is much less than 10ms. Keep in mind pins typically have dirt on them that needs to be pierced through with the probe before making contact. 1ms really is a good number here.

author: Fungus
author_rank: Super Contributor
timestamp: June 12, 2023, 11:55:38 am
content: Quote from: nctnico on June 12, 2023, 08:36:43 amDepends on how fast you sweep.And really, on how often, too. If you only do it occasionally then you can do it a bit more carefully.

author: alm
author_rank: Super Contributor
timestamp: June 12, 2023, 12:59:51 pm
content: Quote from: Fungus on June 12, 2023, 11:55:38 amHaving used both meters with fast and slow continuity, the difference is not between sweeping fast and slow, but the difference is between sweeping across a row of pins vs deliberately touching each pin in sequence making sure you pause at every pin. Because sweeping slowly across a fine pitch device is likely to still go quickly over some pins.

author: Fungus
author_rank: Super Contributor
timestamp: June 12, 2023, 01:25:14 pm
content: Quote from: alm on June 12, 2023, 12:59:51 pmIf it's something you only do once a month then spend the money on something that you use daily. OP already has two meters, one that he says isn't slow.(and I'm not seeing that this meter is...)

author: mwb1100
author_rank: Frequent Contributor
timestamp: June 12, 2023, 03:19:20 pm
content: One thing that that I'm not sure has been mentioned before in this thread is that cheap meters often come with terrible probes. Quite a few youtube reviews show meters that have terrible continuity response with the provided probes but instant response when quality probes such as Probe Master are used. Often you can noticeably improve continuity response by just cleaning the probe tips with IPA. Both of those "fixes" have worked for me.I'd suggest first cleaning the probe tips with isopropyl alcohol. If you still don't like the response you're getting, consider getting some quality probes. You can get the basic Probe Master set for less than $30 shipped (to USA)In my experience and as mentioned before, the ZT-Y's continuity isn't instantaneous, but it isn't particularly bad (when good probes are used).(If you don't want to spring for Probe Master,these $6 generic Uni-T probeswork well for continuity)

author: Hogwild
author_rank: Regular Contributor
timestamp: June 12, 2023, 03:20:05 pm
content: Already mentioned upthread.

author: thm_w
author_rank: Super Contributor
timestamp: June 12, 2023, 11:51:22 pm
content: Quote from: floobydust on June 12, 2023, 04:07:14 amhttps://www.eevblog.com/forum/projects/dmm-continuity-tester-v1-0-better-than-clicking-probes-together!/Quote from: IanJ on March 31, 2022, 04:15:29 pm

author: Fungus
author_rank: Super Contributor
timestamp: June 13, 2023, 01:06:50 am
content: Fluke 8060A:

author: floobydust
author_rank: Super Contributor
timestamp: June 13, 2023, 02:36:09 am
content: Cheater cheater pumpkin eater, Fluke 8060A is using an analog comparator for the continuity detect and oscillator.Otherwise, the 8060A's dual-slope A/D "The total length of the measurement cycle is 400 ms. The length of the integrate period is fixed at 100 ms" a bit longer.

author: bdunham7
author_rank: Super Contributor
timestamp: June 13, 2023, 02:51:49 am
content: Quote from: floobydust on June 13, 2023, 02:36:09 amMost meters with a fast bar graph have to have something to operate that bar graph at a much greater speed than the normal ADC circuit. I can't imagine any DMM with 'fast' continuity actually using the ADC in it's normal configuration.

author: bdunham7
author_rank: Super Contributor
timestamp: June 13, 2023, 02:53:46 am
content: Quote from: Fungus on June 13, 2023, 01:06:50 amAlso note the variable threshold. Not having any non-crap non-Fluke meters, I wonder if other brands typically have multiple continuity thresholds like that?

author: floobydust
author_rank: Super Contributor
timestamp: June 13, 2023, 03:24:28 am
content: Quote from: bdunham7 on June 13, 2023, 02:53:46 amFluke using 10% of any ohms range for a value is just the H/W result of using a comparator and beeper that are always enabled.I'm saying it's not a feature, who wants a beep on 20kΩ range with readings below 2kΩ? for example.My old Beckman/Wavetek (manual range) will beep once and light up the ohms symbol if it sees resistance above the range you are on. I find that useful, telling you to range up.One has a 20Ω/4mA range as well but I forgot the compliance voltage, and I haven't used it for a long time forgot what threshold that has.

author: Fungus
author_rank: Super Contributor
timestamp: June 13, 2023, 04:04:50 pm
content: The best continuity test of any meter I know, Brymens and Flukes included, is the $8 ANENG AN9205A.https://www.aliexpress.com/w/wholesale-aneng-an9205a.htmlIt's quite scratchy, the beeper is loud and it has a very bright LED on the front for continuity.For that price you could tape one to the back of your workbench and just use it for that.It consumes about 2mA in open continuity mode and about 13mA when beeping with the LED lit up. The battery will last a loooong time.The only bummer is that it has APO and switches itself off after 40 minutes.(dons asbestos underpants and waits for the meter nannies to tell me "it's unsafe!!")

author: Fungus
author_rank: Super Contributor
timestamp: June 13, 2023, 05:29:23 pm
content: I made a video of the AN9205A in action, with stock, never-cleaned probes:Was I "zipping" fast enough???

author: Fungus
author_rank: Super Contributor
timestamp: June 15, 2023, 12:19:17 am
content: I did another test of the continuity on the AN9205A because I saw a flaw in my methodology on the previous one - by inserting the probe between the pins on the edge connector I was connecting with maybe two or three pins on the MCU - a big advantage.This time I connected to a single pin and tried to beat the tester - and failed! I zipped so fast that the beep became almost too short to hear but it always flashed the LED (the LED ismuchbrighter IRL than it seem in the video and is really easy to see).I zipped about as fast as I could and it never failed once. It'snotbecause I'm pressing hard, it does it with just the weight of the probe (see video). Who needs gold plating??I tried the same test with mu Brymen and Fluke meters and they did OK but the bright LED is a big plus.So.... I'm calling it, this is the best continuity tester ofanymeter.Edit: I measured the threshold resistance, it beeps below 48 Ohms.

author: vk6zgo
author_rank: Super Contributor
timestamp: June 15, 2023, 12:31:41 am
content: Quote from: BeBuLamar on June 04, 2023, 07:53:08 pmSame here--I was brought up on analog meters & don't trust "continuity", as many of them will still beep with 50 or soresistance, which in some circuits may affect its function.Another thing is, that with some DMMS, the diode test & continuity are the same functions, so any semiconductor junctions may be turned on. The resistance range is normally too low in voltage for this to happen.

author: Caliaxy
author_rank: Frequent Contributor
timestamp: June 15, 2023, 03:26:47 am
content: Quote from: Hogwild on June 04, 2023, 05:14:41 amInstant gratification. Kids these days…

author: Fungus
author_rank: Super Contributor
timestamp: June 15, 2023, 12:06:40 pm
content: Quote from: Caliaxy on June 15, 2023, 03:26:47 amYep, I can easily find the pins on that MCU using my slowest meter. It just takes a two whole seconds to do it instead of 'zipping'.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: June 15, 2023, 11:28:23 pm
content: The situation where I most rely on audio continuity the most is automotive electronics trouble-shooting.Place one probe, usually a Hirschmann clip-on on one side and poke one handed with a standard probe on the other side of a connector.I like a reasonably fast scratchy non latching audio like that on the Bryman 869. There is a lot of information in the scratchy-ness.I will contort myself into a pretzel and lie down in a footwell and work from underneath if I can rather than have to take apart a dashboard. That job is a real pain on many vehicles.And when you are lying on your back the audio is a necessity.

author: james_s
author_rank: Super Contributor
timestamp: June 16, 2023, 12:37:24 am
content: Speed makes a huge difference, if you're tracing out a circuit with a continuity tester or checking all the diodes and transistors looking for one that is shorted you might be testing hundreds of parts, if there is a half second lag each time that adds up to a significant amount of time. Also a lag anywhere is just annoying, even a few tens of milliseconds is perceptible, if you push a button and it takes a moment for something to happen it is annoying and the tendency is to push it again or push it harder.

author: Fungus
author_rank: Super Contributor
timestamp: June 16, 2023, 02:02:40 am
content: Quote from: chickenHeadKnob on June 15, 2023, 11:28:23 pmI'm just thinking it would be very easy to hack an AN9205A (see previous page) to bring out a couple of wires and put the continuity LED on the probe that's in your hand.A light on the probe is something I always wanted in a continuity tester.