I'm rebuilding a vintage (1960's) high voltage power supply with a analog meter and unfortunately it came with shattered glass. I wanted to be sure it still functioned before looking at replacing it and your video was right on the money. Thank you for teaching me not just how to test a meter, but also how they work. I'm happy to report the meter is fully functional!
It really surprises me that while looking (last night and this morning) for information on how these meters work, that I was only able to find this video, and it has told me a lot about how these meters work and how to use them. Thank you for making this video. I will save this for future use! Why it didn't show up in a search last night it beyond me. Maybe I used a different search term or something this morning.
Well, I'm glad you found it! I have a followup video that discusses how to calculate the value for a shunt resistor if you want a larger full scale current rating.
Excellent video. Explained everything perfectly. I picked up some old tube tester gauges this weekend and was wondering how I could repurpose them. This saves me a lot of time.
I found this video at a very apposite time. I have a project and some lovely old meters; now I know how to incorporate them into the project. 73 and thanks.
I ask myself why high quality channels have few inscriptions while s#*% ones have millions?!!!! Alan, I wish you a healthy, long and prosperous life, but are you working to keep your legacy alive forever? We need it!!!!!!!!!!!
Excellent, thank you! I knew how meters worked but was pondering the best way to simply and properly determine their full scale deflection for exactly the types of applications you discussed. Very nice, professional, succinct... what can I say?! Thanks again.
Hey w2aew, this video is pure gold! so entertaining to watch!. I wouldn't personally mind a sequel talking about proper use of these as voltmeters, ammeters, and other applications. All the best.
Not being videos from you that have popped up in my recommended list and that I have watched straight away, I'm watching you channel from older to newer videos, so I'll hit it sooner or later. Thanks!
Thanks for the short and shake test and the link for the meter faces. Also, I like to put diodes going both directions across the meter terminals in case of accidentally putting too much voltage into it. The diodes will limit the voltage to the drop of the diodes. Most meters reach full scale long before the .6 voltage drop in the diodes, but although that much would peg the needled abruptly, the meter would still live through it. Germanium or Schottky diodes could be used for "more" protection. I also use an auto ranging dmm in the ohms setting and the small current from the meter is enough to safely "fs" the meter.
Awesome! I tested an old meter I thought bad, Its good! I adjusted it and its back in service. Thank you so much for a great class. Also downloaded meter basic and its great.
Very Good Alan, Being working in a Meter company for years, analog and digital, We would be Proud To shown this Video to New Hiries . One thing would like to add is even tho the cal point at full scale show correct one thing that might be a problem , is that how it is to be mounted and unit not reading properly. That being cal poise factor, meter laying flat verse meter upright.If you find that there is a Different it can be corrected by repoiseng the unit.on either Tail, or cross arm of its weights .Meters that are made poise is thee Factor in a good meter with its tolerance to Spec. Hints checking Tail poise unit turn at 45* where pointer is Horz and laying on zero, and Cross arm check meter pointer straight up vertical looking at Zero.I did not mean to carry on so just to add to info for those that may have had problems in such, poising movement across the scale. Enjoyed it very much keep them coming Yep thumbs UP in deed, Looking at your Hits Hummmmm great Job . Two Great Shows Here and Mr Carlson labs Boy the knowledge a person can get .. 73's Dale
THANK YOU! Just bought a 40 piece lot of some excellent vintage meters. I plan to clean and calibrate them, then return them to the market so they live on for another 70 odd years. I really appreciate the info.
Excellent demonstration of testing meter heads. Your killing me though. I searched for 4 years for the Harrison power supply meter you have there. Purchased 3 of there power supplies and one of them had a broken volt meter. Finally picked up one at a HAM fest several months ago after years of searching. :) One tip on stuck meter movements in really cheap meters used in chicken band radios. The meter movement pivot pin screws have thread lock applied to them and trying to adjust them to loosen a stuck meter movement almost always results in stripped screw heads. A drop or two of GC radio and tv cement solvent quickly disolves it, you can then loosen the screw about 1/4-1/2 turn to free up the movement and then the thread lock dries again so no need to reapply. Mike
This has to be one of best introductory videos I've seen concerning analog meters. I hope you will add to this presentation with how to build a meter for a specific task/project!!! :-)
I have a few videos that discuss applying a meter to a specific task: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4U-nxdp-LDw.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7OLGswQ7ICI.html
Thanks Alan. Really enjoying all your videos and have built some of the Sawtooth generators. I just recycled a n old dB meter from a very old (dead) induction loop tester and was able to test it 100uA FS using your instruction. Great stuff.
Recently had a stuck D'Arsonval on a Yaesu I bought. I readjusted the pintle set screw; loose direction first & then just a little past the original setting and that fixed it. Also got a tip to just exercise the meter via a signal generator or nearby strong station. Of course if the meter is out of the rig, then you could do that via a PS. Burden voltage is also a concern on cheap ammeters when checking FS current. But not an issue on your to die for equipment. Nice Vid.
Meters, meters, meters everywhere. But did I ever know how they worked or how to test? Nooooo. I do now. Thanks for sharing your knowledge on this topic.
Hi Alan. I recently acquired an Metrawatt MA4E analogue meter, but one with active circuitry (op-amp to create voltage-to-current circuit), with a nice 10MOhm input impedance on DC. I realized that the meter is non-linear, to the proportion that is out of specification of +/-1.5% I suppose that would be of the reading, but have to admit I have not checked the user manual on that point. I have tried adjusting the gain and offset, but could not get it right over the whole scale. The deviation is just to big for my taste. So I have looked in a lot of parts of the electronics, but at last I tested the meter movement itself, to realize that the problem is there. The meter is not linear. It is a 30uA classic d'Arsonval movement. When looking at 0-100 scale, when on 10 it needs 2.8uA and on 100 it needs almost 32uA. The values in between roughly follow the function y=5*ln(x)+76.6 So the scale is like compressed. I don't have much experience with galvanometers and am very curious to solve this puzzle. One more gentleman that also acquired the same type multimeter with similar serial number noticed the same problem, so we are emailing back and forth with our individual findings. First we thought it is something in the circuitry and the op-amp, but now it is clear which part of the meter is responsible for the deviation. Could it be the Hook's law, non-homogeneity of the magnet or... and how to fix this issue? Glad to hear your opinion.
Darn YT notifications caused me to miss this one. Great video Alan. Very well done and very informative. Sometimes when I print the scale I turn the existing face over and attach to the back, since the face is mostly the same. On a few rare occasions I have re-wound the coil to get some meters back working but it is a lot of work. And good watch repair techs and replace those springs :) Thanks again for the video.
Absolutely very helpful video! I'm thinking about making a wide analog meter panel (with about 10 analog meters) for on top of my monitor to keep an eye on all sorts of network information in a fancy way. I'll place RGB LED's as backlights so I can highlight the most important events with RED but I love the good old yellowish backlights as default :) Thanks for this great video!
Nice presentation, the big meter at the opening with the rise and fall is a Scientology E-meter. It is used to fleece people of their money. My apologies to Tom Cruise and John Travolta.
I am embarrassed to admit that I also recognized the E-Meter. I worked one of those for over two years when I was a gullible young man. I am happy to report that I am no worse for the wear. ;)
Great video Alan as usual. Takes me back to one Spring day in Soph EE lab where we learned about analog meters (essentially the only kind available to us in '74 :-) so we'd understand how and what we were really measuring. I *like* and in some cases *prefer* an analog VOM over a DVM. Don't get me wrong - sometimes I need to know if I'm looking at 2.45 or 2.55 volts, but many times a quick look @ an analog VOM "Yep about 2.5 V," is close enough. Thanks again for a good refresher. Gives me a good topic to discuss when I go melt solder with my nephew ...
+jeromekerngarcia Yes, there are many times where I prefer an analog VOM like my Simpson 260 - especially when adjusting or tuning circuits - much easier to watch a meter movement than to follow digits on a DMM. The segmented bargraphs on many DMMs are a very poor substitute for a real analog meter.
Great video as always; I have had a couple of VU meters from an old cassette deck lying about for years. I now know their both 200uA meters! Many thanks.
Very helpful video. And timely, as well. I've been watching fleabay for vintage 0-15 V DC to use in a power supply I'm building but there aren't many to choose from. There are a whole bunch with other voltage ranges and I was wondering if they could be modified for my use. Thanks to your video, I know they can!
+bityard Most likely - and those that have a particular voltage rating on them would probably need a series resistor to make it read correctly anyway (most don't have the resistor built in), so just get one that has the style you like, and make it read what you want.
I used to work on a lot of pyrometers and hi-pot testers with meters and found if you pull off a plastic meter face, do not clean it if you don't have to. I've cleaned plastic meter faces and had them develop a static charge that pulls on the pointer and can makes it stick to the meter face. A anti-static cleaner may fix this problem but I've never tried it.
Awesome video! I never knew anything about analogue meters yet what you just taught had me captivated right through and now I am interested to learn more! Like some of the other posts say "you have a good way of teaching" and put things in laymans terms very well. Thank you for sharing...Oh aye...subscribed too....and you don't need me to tell you what to think of the thumbs downers! NOWT! :)
Terry 01:... If you do learn this stuff I guarantee you that you won't regret it. I started learning electronics last October 'ish and it has changed my life for the better. I'm 40 years old have no kids not married or have a girlfriend. (By choice) and I have to say that this has become an obsession!! And I'm a good way. The amount of learned in such a short time is amazing. An all just from watching videos on RU-vid and getting books from the library. Trust me if you haven't already got into it you should, you won't regret it. Plus it's such a cheap hobby to get into. Electronics equipment is so cheap these days and off good quality.. Hope this message gets to ya and you take my advice👍
P.s.I started in October 'ish 2018 and an already building my own circuits. And all it took was a video I seen one day that blew me away like you said in your comment about this video. If you want to know about more good channels for learning id be happy to let you know the ones that I learned the most from. Good bless and good luck👍
My problem on a Weston model 685 is that the meter movement is actually burned out or open. So this testing procedure won't work. And there is no FS printed on it. How do you find the full scale value in an instance like that?
The DVM meter is only testing the transistors and Diodes under the DVM meters Low Load. Any reasons why the DVM meter is a "Low Load" and not at a High Load when testing transistors, FETS, diodes?
What a hidden gem this video, found u by the eevlog forum about the esr meter. Lets say if I just have a 9volt battery and a few resistors around, using ohms law as u said to find the right resistor for the 50uA full deflection at 9 volts, R=V/I 50ua = 180k ohms 100uA = 90kohms 200uA = 45kohms 1mA = 9kohms Can I tell the meter sensibility using this method? Of course starting with the higher resistance, sry if im saying nonsense stuff, I'm just a hobbyist
How do you test panel meters if they are good or bad because when you measure the ohms of a panel meter it measures very low ohms like 10 ohms so I don't know if the panel meter is good or bad. If a panel meter measures watts how is the panel meter connect to the circuit in series or in parallel? If the panel meter is bad not working can I connect my fluke DVM meter across it in parallel to act like a current or wattage panel meter?
Question for VU Meters: I found a Sony tape machine with two VU meters, one for left and right channels, and when I first input signal the left VU meter gradually went straight to maximum and stayed there. It persists without any power or signal. Does that mean I have a faulty meter? Is there any way to fix the meter without tracking down replacement parts?
how do you troubleshoot equipment that uses those analog panel meters, how do you know if they are good or bad because using a Fluke 87 DVM meter on ohms mode they will measure 10 ohms across the analog panel meters so I don't know how to tell if its good or bad. Older equipment in the 60's and 70's used those analog panel meters to measure voltage, current, wattage, etc. But when measure the ohms across the analog panel meter when using my fluke 87 DVM meter it will measure very low resistance. When an analog panel meter is to measure a voltage what is the difference between an analog panel meter to measure wattage or current its the same thing the analog panel meter is either in series or in parallel. I'm not sure if the analog panel meter is internally different to measure voltage, current, wattage, power, etc.
I did this to boost HP in my car, it used to say 12.4v after a few days of sitting outside due to the Corona Virus. After I did the face plate mod, it now reads 14.6v, enough to start my car even with the low battery CCA. I was able to overtake many EG hatchbacks.
The new multimeters have built in NCV, VFC, VFD. I think the NCV non contact voltage is only for AC voltages for wires in pipes and wooden walls, but can't sense DC voltage in pipes and wooden walls. The VFC variable frequency interface is for measuring AC voltage i think that can have different AC line voltages at 50hz, 60hz, 400hz. I'm not really sure what this VFC really does, do you know? The VFD is to measure motor signals the VFD filters out the motor signals to help measurement. I'm not sure what kind of motor signals you measure using the VFD mode but it filters out the motor noise i think. Do you know what the VFD is used for?
I am still looking for a way to put a 5 digit led display in a Drake L7 power supply. It needs to be able to read from 0-5KV. I have Analog Panel Meters but I am building a new supply and wanted to go with LED's. I have one for the 240v that also shows the Hz. Any Ideas on this Alan?
Hi Alan,, I realize this is going back a ways but,, I'm wondering if I could get some guidance with regard to a A/C ammeter i would like to add a shunt to. The meter is a 500ma range meter and there is no current rating for the movement so,, First do I need to know the internal resistance of the Ammeter? Do I have to get the meter to do a full scale deflection and how would I do that. I actually tried a 10K resistor to do a voltage drop test and the Dmm amp reading said I think 120 Milliamps for 120 volts.. When I tried to take a voltage reading across the ammeter itself I got no measurment. So was there a extremely small voltage drop across the meter say in Microvolts? I would like to be able to use the ammeter to 5 amps.. I'm at a loss.. Hopefully you can help. Thank you.. and thank you for the great video.
Let's see - the meter *should have* read 12mA at 120V with a 10k series resistor. With a known voltage and resistance, you should be able to figure out what the full scale reading of the meter would be. Odd that you didn't see any voltage drop at all. Since you said it is an AC ammeter, are you sure you had your DMM in AC Volts mode when measuring the drop?
Fantastic thank you for your reply.. Yes the meter read 12ma at 120 A/C with a 10k resistor. Yes the meter was set to AC volts,, Is the Current draw of ammeters in the Micro amperage range? Would the Voltage drop across the meter have been so small (Microvolts) that my meter didn't or couldn't read the voltage measurement maybe? Also the meter did not didn't budge at all. I'm lost,, I calculated a resistance size for the range of the meter which was 500 Ma thinking that the 10 k was either too small or too large but I found out that one needs the microamp reading of the meter movement not the range of the meter.. Hmmm So back to square one... A question,,( sorry about this) If i use DC to attain the full meter deflection can I just use a very low DC voltage (millivolts) with an in line Dmm set to uAmps to attain the meter movement amperage draw? Thank you again for the reply and your Help..
I liked your video. I have a 0 - 10 Amp analog meter, and a 0 - 15 volt analog meter. I tested the voltmeter and the needle wanted to move backwards when in reverse. Could I adjust to have 0 centered at the top? I would like to use these meters on my HO train layout.
Have you ever compared a Cb type modulation meter to a scope? And also wondering how those modulation meters work. Possibly the increase in voltage from the unmodulated signal. Wonder if 100% is actually 4x.
Many, many moons ago, a class of polite and studious trainee radio officers were studying a Bander-copied handouts in an introductory class on meters and movements. When the class finished, one student gathered his study books, notes and papers, then loudly kissed his handout with an exaggerated "mmwah!!!" Looking very puzzled, the entire class and lecturer stared at the student with eyes wide.. After a few seconds of silence and amazement, the trainee asked "would anyone else like to kiss my D' Arsonval?"
Great video! I have an ammeter out of a classic car that only has charge / discharge markings (needle in the center when off - 12V system) that I would like to test. It uses a shunt wire, that cannot be removed from the car, in parallel with the meter. I guess the resistance of the shunt would be too small to measure accurately with a DMM. I would guess that a very small proportion of the charging current would be passing through the meter itself. So, I have it on the bench currently and I'd like to test it out to see how much current would actually give full deflection. Would a 10k ohm resistor be of use for this test? I'm thinking I'd have to use a lower value resistor than you would be using here? Do I even have to use a resistor? I have a bench power supply as well.
You can certainly start with the 10k resistor in series with the meter. Start your power supply at 0V and slowly start bringing it up while watching the meter. If you get to your supply's maximum voltage and the meter still hasn't reached full scale, then start over with a lower value resistor, etc.
@@w2aew Wow thanks for the quick reply! Ok, will try that thanks! I had the ammeter hooked up, with a little incandescent test lamp for a load, like this a couple days ago just to see if it was working: PSU (+) ---Small Lamp---(+)Amm-Amm(-) ----PSU (-) I had the power supply dialed up to 11V, the lamp was brightly lit and the PSU display was indicating that it was outputting 280 mA. The ammeter was showing just a little bit to the "discharge" side. Maybe 3 or 4 needle widths. Does this sound like things are functioning correctly?
I'm hooking up an old tachometer to a newer motor and have added resistors to lower the current. The tachometer has no electronics and the output from the motor is ac. would I use a diode or zener to remove the dc component?
is there any way to move the zero point to the center? my adjustment goes to about 30%... is there an adjustment for the other end that would allow the whole thing to drag to the middle? I want to translate my left-zero meter to center-zero
Not easily. The tension spring design is likely a little different on the "centered" models, so it likely isn't practical to expect that you can adjust one to be a center-null meter.
Great Video I think there are two different kinds of analog meters, Type 1 shows the needle proportional to the current (I) Type 2 shows the needle movement proportional to the square of the current (I^2) Yours seem to be all only linear, right? How do you know you have a meter that reacts to I^2?
Lately, some of the links for your notes take me to your website directly, and don't have any reference to them there that I can find. This is one of those instances. Are these links there somewhere, or are they simply not working properly? I have somewhat of a dependence on these notes for handy reference offline at my bench. All very useful. Thank you
My host for these files changed the way they're mapped, and I have been fixing the links one-by-one. Here is the link for the notes for this video: www.qsl.net/w2aew/youtube/AnalogPanelMeters.pdf
Hi there, liked your video and efforts to explain. I've checked the website, the address link is invalid, but if you choose the main domain address, you're fine, or just use the aforementioned address but leave the 2 out that'll work .. cheers
It all depends on the design of the particular meter. Some are more forgiving than others. In general, it is a bad idea to peg the meters. It can overload/overheat the coil, and can damage the movement and needle if it smacks the stop too quickly.
Who would down-vote this video??? It's complete and entirely factual. I didn't notice a single mistake or omission of information. It doesn't drag on and is presented in a concise and enjoyable way. (I can tell you with 100% certainty that these down-voters don't have a better video or any videos at all.)
Well... I can tell you that your videos are great. I've been an EE for 28 years and I enjoy watching how other engineers approach and solve problems. You have one of the best electronics channels on RU-vid. Thanks for all the great videos.
I've been looking at that across a lot of presenters; I'm guessing the dislikes are about 0.5% to 2% of the likes, no matter what, at least in the kinds of things I watch. At 10% or so, you figure something went wrong somewhere... maybe a bad production decision, whatever. Then actual content issues go up from there!
Hi, I like your video! My question is how to use a new style vehicle speedometer (that sweep tests with computer) in a analog circuit like a cb radio watt meter? Thank you!
Another great video, Alan, thanks. Question - I have a Weston Model 901 DC Ammeter and at the bottom it states to use it with an external 50 MV shunt. Can you explain the units of this shunt? Wouldn't this be a shunt resistor? I think also have the shunt somewhere but need to dig it up. The ammeter has two scales 0-15 and 0-150 with no switches anywhere. I presume I would need to use two different shunts differing by a factor of 10 ohms?
A "50mV Shunt" is a low value resistor that will have a 50mV drop across it at the rated current. It is designed to work with meters that will have 50mV drop across the terminals when operated at full scale deflection. Since the meter's coil resistance will be significantly higher that the shunt resistance, the parallel combination will still be very close to the just the shunt resistance. Thus, it is easier to specify the shunt for the voltage developed at the rated current. For example a 50mV shunt for 10A will be 5mOhms. Yes, you'd need different shunts to use both scales.
@@w2aew Ok, that makes sense. So the shunt acts as sort of a current limiting bypass for the meter. The coil resistance is just under 50 Ohms, so with a 50mV shunt, the internals are seeing only a 1mA. I opened it up and the wiring is around 30ga, so its pretty delicate yet the terminals are pretty big to minimize any resistance in the connections. So for the 150A scale the shunt must be pretty big to bring the resistance down to 50mV/150 = .33mOhm. And the wires to and from the shunt and meter would need have very good and clean connections. I don't even have a meter that can measure such a low resistance.
@@Kurt1968 Correct. Measuring resistance that low definitely requires some special equipment, 4-wire sensing, etc. For these high-current shunts, the resistance is so low they typically spec'd them by their voltage drop at rated current. To learn more about current shunts and how they change the scale on a meter, see this video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4U-nxdp-LDw.html
Thank you for this video. I learned so much and it jogged some memories from 40 years ago in my "computer electronics" class in High School. Lol. I'm working on an Autotransformer (Variac) that takes 120vac in and produces 0-140vac out. It came with the appropriate Emico voltmeter installed. The transformer is in fact producing 0-140vac but the Emico is only reading approximately 70vac while my Fluke DMM is reading 140vac. The Emico has no FS information printed on it. I assume at one time it worked correctly some years ago. I can see a rather large resistor in series with the coil and this all looks unmolested. There is no zero screw but the pointer is resting at zero. Can you tell me if this meter is shot or is there something I can do to get it reading FS correctly again? I appreciate any feedback or help. Thanks.
It certainly is possible that the resistor has increased in value - it's reasonably common, especially for older carbon resistors. That would be the first thing I'd check.
@@w2aew well Sir you are 100 percent correct. It's Brown, Black, Orange, Gold. 10k ohm +/-5%? It's reading 19.7k ohms on all 3 DMM's I have. Which makes sense considering it's basically doubled it's resistance and it's reading half scale. Next question is how do I determine the replacement resistors wattage? This is approximately .500" L x .250" D. I'd guess either 1/2 watt or 1 watt but how do I confirm? Thanks again. Robb.
@@robbo6460 easy. Assume that the full 140V appears across it. Power is V squared divided by R, so about 2W at the full 140V. You probably want to give yourself a safety margin and us a 4 or 5 W resistor.
I would add a couple points. The springs serve a double purpose. #1. It is the electrical pathway to the coil itself. #2 as was stated It helps to keep the pointer stable,
good, great, important point which the uploader skipped. Material is phosphor bronze which is a good conducting spring material. Steel is bad conductor and also corrodes during monsoon. Kishore kumar from Chennai, India.
I am trying to repair an old tractor dash cluster and both the Fuel gauge and Temperature gauge are weather bad with rust any chance these are common and available. Electrically they attach and mount to a PC board with 3 screws each. The screws are very unique with intragyral contactors..
Gauges in automotive and other motor vehicles are generally not D'Arsonval type meters, since they wouldn't generally standup to the vibration in these environments. Probably not much you can do other than exact replacements or aftermarket units that are intended for the motor vehicle application (although these latter units would likely not fit the OEM location).
Great video. My trusty Multi Meter has gone open circuit on the coil. Its 18 microamp FSD. Can you do the opposite eg. Make a 100microamp FSD read FS with 18 microamps instead of the reverse with a shunt. Its just I cannot find a 4.5inch 18 microamp FS meter
Yes, for a voltmeter, you include an appropriate resistor in series with the meter, and put the combination across the output of the supply (in parallel with the load).
@@w2aew To perform the test, you begin by applying voltage in millivolts. The shop-grade/commom/hobbyist voltage supply usually outputs in whole volts only. I was wondering if a circuit can be designed to lower/drop volts down to millivolts.
Hi and thanks for all your nice videos! I hope you see this question, and answer if you will :P I want to know if it is possible to build a test setup using of-the-shelf components to measure the resistance of tracks on a PCB. I mean using some voltage meter chips and microcontrollers, some shielded cables and stuff...since I do not have access to any quality measurement gears. I want to try with 4 wire measurement and maybe double kelvin bridge...is there any chance or I will just waste my time?
+Saeid Yazdani Sure - it is possible to make a 4-wire system to do this - a constant current source and a resonably accurate voltmeter are needed. However, at some point, the accuracy of your homemade system will have to be checked against "known good" instrumentation.
I have one of that china made 40watt laser engravers, it was cutting poorly and after watching your video, I started suspecting that the analog ma meter was giving me the incorrect mA measurement, After un connecting it and hooking up a voltmeter in its place, i gain 50% of the power back, Which means the analog ma meter that was installed is somehow dropping the power, My question is, How do i find the correct resistor value to have both the analog ma meter displaying the correct mA draw and making sure the cutter gets the power.
It is impossible to say without knowing details about the meter (full scale range, coil resistance, etc.) and how it is hooked up. Disconnecting the ammeter and putting a voltmeter in its place doesn't make any sense to me - ammeters are connected in series while voltmeters are connected in parallel - they are not interchangeable.
@@w2aew the measurement range that is needed is from 4mA to 30mA, the mA meter is connected on the Cathode side of the Co2 laser tube going to ground, the multimeter I used is in mA mode and I simply connected the probs in place of where wires of the Analog mA meter was. Is that wrong?
@@w2aew Thanks for the reply, I got it all sorted out, I basically tried a few different resistors till I got the right one which I settled on a 20ohms. Nonetheless, your video helped me learn something new, Thanks
