Understanding How To Test Voltage Drops (Part 1)

[@FacilitiesDIY]

This video combined with others will be very helpful. I find that there’s not ever really one video or person that shows it in a way that everyone can understand, but the plethora of content creators like you who explain it in their own way together, with all those compiled, it helps astronomically. Also your example of the hills is very easy to understand

[@alexlongpre4527]

The best water analogy to me is to see voltage as pressure and current as flow. Other than that, it's a very good explanation of the concept.

[@sambamcunninghamm]

Resistance on the negative side was extremely helpful

[@als1023]

Same

[@abdul-kabiralegbe5660]

That hill analogy is great. Thanks.

[@salceti]

The best part was explaining that the system already knows that there is more resistance to overcome to get the voltage to 0.0 When it reaches the first hill, it knows that there is at least another hill to overcome, maybe even more hills, beyond the second hill but the voltage readings will tell you if you have found all the hills after the last one by reading near zero.

[@thomasherring6640]

For a DIY'er, voltage drop is one of the harder things to properly understand. Thankfully, I Learned this stuff many years ago in college, and it has served me well over the years. This is one of the best explanations I've seen of it on KZbin. Kudos to you for tackling this, and explaining things that are typically very difficult for the home gamer.

[@thekeeneygarage]

I think the video was good. When teaching new people, I usually describe it as a "difference" or "delta" in voltage. ie. at the B+ you have 12.6V and at B- you have 0V, the difference is 12.6V, that's why the meter says 12.6V. I use that same approach across resistors. Then later, after they get the "delta" approach, I bring up the "drop" across a resistor as opposed to starting with "drop". Either way, your video still gets the point across & I look forward to the next one.

[@DoubleRRestorations]

Excellent video. I'm an electronics tech and you did a great job explaining this. I have never really liked mechanic work, but as complicated as cars have now become, I really enjoy troubleshooting these electrical issues that develop in them. I think you guys are very thorough. I wish there were shops in my area like yours!

[@djmobileautoservices]

Appreciate the video Mr Sherwood. You and guys really go beyond to help techs get better

[@supercleaner]

You're explaining what happens during a power "brown-out" in a house. Every electrical device dims or suffers equally as power is shared incrimentally according to each individual load. I'm subscribed. Thanks.

[@michaelmcnicholl608]

I understood the way you explained this subject really well. I have had trouble understanding electrical issues in the past and still do at times but you really clarified some basic things that help me understand drops as a whole. Thank you. I will just say that you have one thing that you do (and I do also when I get excited about explaining something) that you might think about, and that is you jump around trying to explain something and then change to a different way of explaining it easier or different. But overall great explanation for me as it really helped!

[@pontiacsrule8761]

It was extremely helpful. That part about the hills makes sense. Great job explaining this..........

[@als1023]

Same

[@garymichalak5379]

I’ve been doing auto electric for many years, sometimes I have a hard time explaining how a circuit works, your video was the best apology I’ve ever listened to. I can now explain it to other people much easier now. Great video, you have me as a subscriber.

[@Razor_36]

Man I have watched a bunch of videos on this stuff. I work as a fleet diesel tech so I see the same equipment every day. I absolutely hate electrical for the same reasons people hate firearms- they don't understand them. If people would start with understanding Ohm's law and then move on to learning how to read a meter and what the symbols are things would start to click. I thought you did an excellent job of explaining the importance of checking both legs not just the positive. Most people think the negative side is a completely dead wire and don't truly get what the word circuit means. I was one of those guys in the beginning. Great job man. A+

[@sambamcunninghamm]

This video was extremely helpful. I finished a year long automotive class at mohave community college. (Which means i have a small amount of knowledge and have read A automotive technician book) your videos helps further lock-in the knowledge and information and also lets me know the tools necessary to do a quality job! Keep up the great work!! Thank you! God Bless!

[@BillyBaker-yn2tr]

Man, what a blessing this video was I’ve been an engine installer for 22 years shop i worked at the Owner retired and now I’m forced to learn how to Diagnose I’ve searched and search for the best description of Voltage drop trst and as soon as you did The description on the little whiteboard, it just clicked thank you guys For taking the time to teach what yall learned over the years, you guys have no idea how much people like me Appreciate these These videos!!

[@brentv9901]

Not bad. Honestly, over the years I found out it doesn't matter how you explain it. One analogy will work for one person but not the next. Getting good hands on experience is the best and they'll finally have that "uh hah" moment after a while haha

[@anthonytimperio1254]

Watched a ton of videos on voltage drop and just couldn’t grasp it. The hill analogy cleared up a lot. Thanks.

[@andrewshedron425]

If i can only pick one person to be stranded on a deserted island with I know who i would pick! Stunning!! ❤

[@sollykhan2385]

This video has to be the BEST on Ytube regarding this elusive topic that appears to stagger the best of car electricians, i can honestly say(with deepest respect ) that every 'Gray' hair on your head has been earned with intense hard work and time consumption, Sir i salute you, please post more of these fantastic educational material, the only thing that appears to concern is why only '114' comments from 9.2K views, are people that busy or indifferent that they cannot show gratitude by posting a nice feedback for someone's effort? 🤔

[@sgtniehaus]

Great video Sherwood. I personally love to use the word current when using the water flow as an example. I even used as an example for a mechanic yesterday that couldn't figure out why he had 12 volts at the battery but no tail lights.

[@mzayts7852]

Thanks Sherwood if I had any questions about any of that before you've cleared it all, makes it feel much easier knowing different ways to test it.

[@mattp0058]

I am a complete novice DIY guy KZbin Certified lol. First watch I was confused but after watching again everything made sense. The hills explanation clicked on the second watch and made sense!!

[@ThunderbirdRocket]

Nice 👍🏼 ! 🎯

[@kyleotto4539]

One of the better voltage drop explanations I've seen. Only two suggestions, don't change the reference like you did at the 21:00 mark, for young guys learning they might confuse that it's a requirement to "test the ground side". The other is just about how I think - leave the water analogies out. If a pipe breaks water keeps flowing, if a wire breaks current doesn't.

[@ThunderbirdRocket]

Tremendous tutorial ! Excellent analogies !! Clearly demonstrated and explained in simple practical terms for us in the repair shop process / issues . Thanks mate ! 👊🏼

[@MidnightMechanic_Rob_M]

I would recommend showing measuring the circuit before adding the resistors to show a “known good” situation in real life, in addition to your white board sketch, just to prove the concept and show what the voltages would be in a good circuit. Then when you add the resistor, and see the voltage drop it gives a before and after, it makes more of an impact. My two cents. Great video though! Very helpful. Really appreciated the comment about melted connectors.

[@RayMacksKitchenandGrill]

This is totally helpful...I'm loving your tutorials.

[@mrjed84]

Hi thanks for your input. I thought the early part was well explained using the white board. But you seemed to go quicker as it got complicated . I will need to to watch it a few more times. Well done thanks again

[@mariomazerati]

By far the best thing so far to test for a voltage drop on power and ground circuits is a Load Pro.

[@onlineretail3550]

Basic concepts on how an electrical circuit works was explained and demonstrated well. “Load that circuit”when testing “Test both sides” Good explanation of the different types of resistance. Make more electrical tshooting videos😊

[@ryan.mullen]

Great video. I love these videos of you teaching. I could watch these all day long. I thought of something that might be cool for you to include because it’s kind of relevant. Can you touch on load testing a circuit? When to use different loads. Maybe LED vs incandescent test lights? I have a bunch of load testers from .5a to 2a up to 4a.

[@ThunderbirdRocket]

Yeah ! This is a great topic - one that is a a little bit scary because of the fear of harming a low amp (delicate) component such as a computer module . The question of what is the correct answer to using LED vs an incandescent test light is key and I’m looking for advice too .

[@anthonygolwitzer]

Excellent description. Fully understand, would want a more in depth power probe checking. But fully understand the volt meter explanation

[@Peter-tf2uc]

It's actually a great explanation. Resistive loads are just added in a circuit

[@Peter-tf2uc]

I would maybe simplify the wire layout a bit so it's easier to see what is plugged in where

[@Peter-tf2uc]

I would maybe simplify the wire layout a bit so it's easier to see what is plugged in where

[@Peter-tf2uc]

I would maybe simplify the wire layout a bit so it's easier to see what is plugged in where

[@Peter-tf2uc]

I would maybe simplify the wire layout a bit so it's easier to see what is plugged in where

[@marks2254]

Probably too late for comments. The subject was well explained, great job. The problem I had was that I couldn’t see the meter screen or the entire circuit when you were taking your measurements. I think to make the process more visual, you could’ve drawn the circuit on the white board then after after you made the measurement, go to the white board and show the lead locations so we could easily see where they were in the circuit. But you did a good job. I liked the hill analogy.

[@beakittelscherz5419]

Honestly, the "hill to overcome" analogy to explain resistance felt rather confusing for me. But I watched several other videos before that,- so I knew what you wanted to explain. So I watched the full video. And I think it's good. Bc, other people may profit from it the way it is. It is a complex concept, but once you get your head around it, it's logic.

[@trueblue8415]

Very good. Liked understanding resistance on ground side. Very good.

[@sjsnopek]

Bad connection = resistance = "hill"; Ideal connection = no resistance = "flat"; In more scientific terms V= I x R where V is the voltage drop across the connection and R is the resistance (I is current greater than zero; i.e. the circuit has to be connected and electricity flowing for this work). With a constant current, as resistance, R, goes up (bad connection, corrosion) voltage V (as measured by the meter) goes up. Thank you for a great video.

[@stevecoats2164]

The multiple hill analogy cleared it up for me as well. Thanks!

[@Mr2004MCSS]

I enjoyed the video. The easiest way that I learned voltage drop was using a meter and if testing the positive side of the circuit, put the positive lead of the meter to battery positive post and the other lead to whatever point of the positive side of the circuit I'm testing and the number on the screen is my actual voltage drop. I don't have to subtract numbers to get my voltage drop. Negative side of the circuit, I'm hooking my ground side of my meter to the negative battery post and touching my positive lead to whatever point on the ground circuit I'm testing and this gives me my actual voltage drop. As you stated, in order to have voltage drop, you have to have current flow thus a loaded circuit. You also have to know what is an acceptable voltage drop number depending on the type of circuit and component you are testing. I have read various ball park figures depending on if it's a low or high current load that range anywhere from less than 50mv to as much as 2.5V on a starting circuit.

[@theroyaltyautoservice]

Yeah those are the "ballpark" numbers. Smaller load on smaller wires must have a smaller voltage drop.

[@danielschmidt2721]

Excellent video man I’m going to use this to teach people voltage drops

[@steveharmon9000]

I found this to be easy to understand and thorough. i have a hard time wrapping my head around some of these concepts so i appreciate the attention to detail. It was important to me that you repeat certain things, expecially if you don't load the circuit you're wasting your time. Also you stressed the importance of testing both the positive side and the negative side which is an abstract mental puzzle until you explain it.

[@stitchbmx]

This was a simple explanation on voltage drops. I liked the video. My problem is finding intermittent shorts in a harness when a wiggle test is unsuccessful. All your videos are always educational and informative.

[@frankdaiii6403]

Good video! you may want to take the time to mount the circuit on a piece of plywood with single wires like your dry erase board diagram. I've found people will grasp the concept faster if pos and neg are separated and the "circle" is easy to see. I use a garden hose with a spray-gun attachment to describe voltage drop. pressure is voltage, kink is resistance, flow is current. Kink the hose a little. Both sides of the kink have pressure. Pull the trigger (activate the circuit) and you can see there is very little pressure at the nozzle (voltage drop). release the trigger and both sides of the kink will pressurize equally eventually (full voltage in a circuit that's off). EXCELLENT idea using the multiple devices! Keep up the great work!

[@dearinghoward]

Great video, I think all to often people get overwhelmed with the thought of the complexity of electronics, sometimes looking at it as an overall concept and keeping it simple helps understand the simplicity of it in general, I used to be really confused with this situation as easy as finding a problem with a dim light. I went through an electrical school with Chrysler that helped me understand it so much better. But most of us make it more complicated in our own heads by over thinking the idea. Great video

[@Scofflaw_k10]

I enjoyed the video. I’ve already got a fair grasp of electricity but this is a good demonstration and the hill analogy is nice.

[@randyduncan8863]

Man your videos are some of the best on the Internet seriously they are

[@TSpain]

Excellent explanation, examples and demonstration of basic fundamentals! Great job, not confusing at all.

[@vladimirtc9574]

Hey . Let me tell you something, this was very helpful. I am familiar with tester, resistance and voltage drop, but I never new if you put both terminals of this tester on The same pole it was showing a resistance . Using this technique I found less in an hour were my bad ground was . It was awesome. Thanks a lot

[@adm7812]

this 17th century naval captain looking person explained it well. Looking forward to the next one since this is an extremely important area of knowledge. thanks for sharing and your hard work.

[@rolandos64]

For those who can’t comprehend “Potential difference “. All it means is that it’s an ”Audit”. The DMM is telling you what it found. It did an audit from both sides. The result is Your reading. It does not tell you who has what! Just the total difference from one side to the other. One side maybe had 6v and the other had 6.5V. Collectively that’s 12.5V. Therefore the “potential difference is 12.5v.

[@steveramoso962]

wow.. i wish i learned this earlier... Thank you guys i learned a lot from you guys specially quality works and dedications on small issue which are big factor on the long run..

[@c00cs1]

This is something I struggled with and you explained it very well, I have a much better understanding of it now, thank you for this video.

[@BryanFitzpatrick8BellsBrewing]

Thanks for sharing your knowledge. The ground side testing and power must be on was very helpful. When it comes to automotive electrical it’s like how do you eat an elephant, one bite at a time.

[@montielgustavo]

Thank you a lot for your video! Excellent explanation! I need one advise, I need to replace a keyless entry receiver module of tahoe 2013 and I need to if necessary to disconnect the battery for this operation. Thanks in advance!

[@1983dmd]

You are a GREAT teacher !!! 100% clear and easy to understand. Wow!

[@Rob-u1p]

Video was very clear, I am a trainer for my company and our basic electrical class is very similar

[@joedemedeiros6415]

Thank you, very informative video Love how you got to the core of simplify it .

[@docohm50]

You should teach them Ohm's Law first. You have a series circuit that has a lamp (32.5 ohms) and a 2 ohm resistor and the resistance in the jumper cables/alligator clip bad connection which equal 13.4 ohms. Your total circuit resistance is 47.9 ohms. Your total voltage is 12.45 DC volts and your total current is 0.26 DC amps. In your homemade circuit you actually have several bad voltage drops. You have the 2 ohm resistor and the bad test leads and connectors. The engineered intended circuit was a battery, a lamp rated at 32.5 ohms and the wire to the lamp and back to battery which should be 1 ohm or less not 13.4 ohms from bad connections in your example. I followed along what you were saying but I think if they knew Ohms law they would know what the reading should be before taking a meter to the circuit. I really love you videos. Keep up the great work!

[@GatesheadEddie]

Well done guys good vid, I use a load pro for testing of voltage drop and I find it very useful, you guys should do a video using one, an incredibly simple tool that adds another dimension to the multi meter

[@dannyc1657]

Great video, your advise to try not to disturb or unplug connections during testing is good also. if you have a loose or corroded connection, unplugging and reconnecting could remove or disturb the corrosion or tighten a connection that was causing the problem in the first place. 👍👍

[@anrescue]

I believe on the power probe if the tip voltage is not within .5 volts of the battery voltage it won't beep but will light the color and show the voltage. You might be able to change that setting. The power probe Hook & IV show battery voltage & tip voltage so a voltage drop test is right in your hands for positive & ground...very usefull.

[@chrisrainville6324]

30 year Gm tech here,love the voltage drop videos,great job Mr.Sherwood!!!!💯💪🏻

[@tomlombardo85]

First of all, thanks for all the time and effort it must take to make a video like that , it was great. Voltage drops or electrical problems are my weakness but this was one of the more easy to understand and clearly explained. Bringing the light box in at the end did muddy the waters a little bit but all diagnostic techs usually have a variety of resistance (bulbs) they introduce into the circuit so I do get that. I'm looking forward to watching part 2 and yes it did help !

[@fadilabban5769]

Hello from France, amazing video really, now it is clear in my mind how to test an electric car problem using the voltage drop method. I hope you can do a video on a car, just simulate an electric problem and show how you find it. Thanks so much

[@saiautorepairs]

Awesome video. Can’t wait to see the next part on how use the scope for voltage drop Thank you for taking the time. To make this video

[@isaacgomez7675]

You explained it great thank you for the video you helped me understand what a voltage drop is and how it works!!!

[@arthuraucar3696]

Very informative video..! I will say that I'm not too impressed with power probes, however I understand that in most cases it is helpful. Also, you must ask yourself twice before probing a circuit to power or ground. Thanks again for another great video..!

[@autotech1106]

Your explanation of the mountains was helpful to understand there is a connection issue on either side+ or - side. I really appreciate you explaining that you have to test the positive cable going to the starter while cranking. That process could easily be done wrong. You might think about explaining the load pro. I don’t know if that’s something that would be beneficial or not I use it and I love it.

[@AfflictionSuzukiGsxrLosAngeles]

I understood perfectly. I finally understand

[@stephenhill2238]

Great video on simplifying voltage drop and how to find it, especially using the meter. i think your reference to the circuits wirin diagram for the check points is to often overlooked. I for one never think about it.

[@justwelltariang2456]

I got it Sir but please make a video on a board along with the drawing that would be extremely helpful especially for the very important measurement like the voltage drop. Because changing the meter leads from positive to negative during measurement is a little bit an issue i believe for a lots of beginners. love it

[@williamcruz4291]

Great video! Very easy to understand for me at least. Ever consider making a parasitic draw diag-lesson video? Def would like to see one of those! Love the content keep it going!

[@MattG171]

Great video as usual. I like the kinked hose analogy personally. My 2 cents.

[@tylerwilliams3868]

really enjoyed this video as a jeep master tech. i love electrical work and problems! totally think you explained voltage drop and what it is and showed it perfectly the first bit (drawing and your setup) i will say i got confused when you added the two voltage drops at a time and how to check for that. love the little rig you made but maybe just using a lightbulb set up would of been better. anyways very excited on voltage drop on a scope because i love my scope!

[@rmacuil5]

Just the video i was waiting for from someone i look up to 🙂

[@KOBBSdiesel]

Auto elec student here. Explained and did demo verywell

[@richo926]

A follow up that would help me is in your example of a starter circuit. Voltage drop could be caused by resistance or in this case a weak battery which falls flat on its face under load. Maybe a quick followup on that type of diagnostics and testing and different methods. Thanks, great content!

[@tedgtfan]

At the battery post you would see a bad battery under load because it would drop below the 8.5 threshold, some say 9.5 to 10 but for sure at 8.5

[@KissTamas3]

Brilliant video. Many thanks. I didn't know that voltage was so smart. :)

[@Grunter123]

Thanks Sherwood, I found that explanation & demonstration very good.

[@antonydunn3742]

Great video.The hill analogy works for me 👍.

[@jimjim2119]

Very excellent instructions for a DIY non-mechanic. I did find the power probe and loading the module was confusing.

[@Zachgregor422]

Looking forward to seeing your class at tst.

[@wonjat5]

Thought your description was very good, I guess a lot depends on whether your subscribers were taught Ohm’s law at school. Hope a lot of techs watch this. Thanks for a great teaching effort.

[@robbiesharp311]

Love 💗 the way you ask for feed back!

[@robertparamore2863]

What's the difference? If you have a water hose filled with water pressure. Pressure is your push ( or your voltage). Water is your amps. The amount of water your pressure can push is your current. If you start poking holes in your hose ( simulates voltage drop), your difference between the start and end of your hose will be different. I replace or go around a lot of GM connectors. Yes, fretting is a thing. Sometimes I'll try some fine valve grinding compound and a generous amount of dielectric grease. Thank you for sharing your wisdom. We are all in this together.

[@robertparamore2863]

Do electrons flow positive to negative or neg to pos? Electrons are negatively charged by the way.

[@tedgtfan]

"The amount of water your pressure can push is your current" is partially correct. The amount of water or amperage that can be pushed is determined by resistance. That being size of pipe or wire and what type of loads or restrictive variables that may be in that line slowing down or limiting its flow. The voltage or pressure only determines how hard or with how much force it can be pushed as opposed to amount that can be. " If you start poking holes in your hose ( simulates voltage drop), your difference between the start and end of your hose will be different." Yes the Pressure/Voltage will change but the amount of water/amperage will remain the same as what went in same amount is what will come out, here again determined by the resistance applied.

[@tedgtfan]

@@robertparamore2863 Electrons are the lightest particle so they are easier moved than heavier protons and neutrons being neutrally charge weigh somewhere in between. So neg to pos flow.

[@steelcamel5626]

hello, great teaching.......do you, or how often do use see corrosion on pin connectors as a cause for voltage drop. tx.

[@JoseCruz-wn8bc]

Great video would love to watch utilizing scope..I have had modules cause volt drops and would to see if a scope can prove that

[@jnhudspeath]

That was helpful im starting to understand it thank you especially the ohm ing it out part the starter reference saying you better be checking it while you’re cranking it was excellent

[@drbyers]

It was a bit complicated but good enough to help me understand. And I HATE electrical diagnostic.

[@kamaluddinimamali7441]

Great thank you. Can you do a video on oscilloscope testing from A to Z

[@ThunderbirdRocket]

Yeah ! 👍🏼

[@mrh8637]

When you're putting bulbs in to load the circuit, how do you know what bulb to use....ie resistance wise, that would be a good vid along with using different test lights to load circuits, thanks good vid

[@toms66gtstang]

Good video, maybe slightly confusing to people new to the subject. I saw a video, by Pete Meier, on the basics of a circuit & voltage drop. The hiw he put it stuck with me. All the voltage in a circuit will be used up by all the loads in the circuit. If a good circuit has 2 of the same bulbs 1 will have a 6v drop & the second will use up the other 6v. ( numbers for simplicity). If it has 1 bulb & one other load, such as high resistance from corroded connector the same thing applies, the amount of voltage each load consumes might be different, but they will both total the 12v. If there's an 8v drop at the light then the bad connector will show a 4v drop.

[@Ironblank1]

Thanks for your time brother.

[@sheerwillsurvival2064]

Great video great explanation the hill works for us runners at Least years ago😁I used to run 👊🏻👍🏻 more like this please

[@josephfelten4336]

Fantastic Job!! Enjoy your guys videos.. 👍🏻

[@tibortorok6343]

Kissé zavaros, de azért érthető. Hiányzik az ép áramköröni mérés. Köszönet

[@welliott780]

Actually pretty helpful definitely want to see u use the scope

[@jerrymotta9379]

I usually tell my students that if there is one load in a series circuit that all the voltage should drop across that load. If all the voltage does not drop across the only load, there is unwanted resistance in that circuit. If there is more than one load in the circuit, the sum of the voltage drops should equal the source voltage.

[@ron.owensby]

I was tring to think how to say what @thekeeneygarage said. The thing that I thought was confusing was when you talked abut measuring from Negative to Negative. I know what you are saying, all components are more positive on one side, they have a potential difference. I'm not an automotive technician, I (Used to) work on discreet components in a small area. All those wiring harnesses very intimidating to me!

[@NeilTomkins-t5u]

Great video, confirms what I’ve been shown.

[@timk8814]

Helpful information. I already understand voltage drops. I enjoy seeing the various methods. What are your preferred backprobes?

[@theroyaltyautoservice]

AES Wave had good ones. I really liked the ones that came with the original ATS Scope but I haven't seen them for sale in years.