How to use a Multimeter for beginners: Part 1 - Voltage measurement

[genezero12]

What type charger can I use with the 12 volt battery? Thanks

[mjlorton]

@genezero12 If you look at the video details / show notes you'll see a link to my Amazon store. There's a category for batteries and chargers where you can find a 12 volt battery charger. cheers. Martin,.

[StopSocialismUSA]

I just bought the fluke 179. 330$ tax included.

[mjlorton]

@StopSocialismUSA Excellent buy, I'm sure you'll enjoy it.

[lolek12345kmet]

I am going to say AC voltages since it takes much less mA to cause serious damage + when you touch AC line your muscles contrats(specialy at higher mA) and they just freez so you basicly grab the cable and never let it go, while with DC you get temporary shock but you are able toremove hand if it doesnt kill you in first place :D

[mjlorton]

@lolek12345kmet Thanks for posting a response...see Part 2 for the answer.

[kibi15]

...and another thing. Forget about all this urban myth about AC giving you a chance to "let go". At 50Hz the CYCLE lasts 0.02 seconds. The voltage will switch between 282.2v positive to 282.2v negative in 0.01 seconds. Even Chuck Norris wouldn't be able to react that quick! Well, maybe he could but, you get it. In America it's 60Hz giving you even less time to "react"

[kibi15]

I'm going with AC being more dangerous.

The reason why is that DC voltage is measured at it's peak, usually because it does not vary a great deal from it's peak measurement. AC voltage is measured as it's RMS value (true RMS meters). The RMS value is 0.707 times it's peak value. So, an AC voltage measured at 200v, has a peak value of 282.2v. Therefore more current passes through your body at the peaks of the AC RMS voltage than the same DC voltage making the AC more dangerous

[RapshadyAvin]

* AC is dangerous

[RapshadyAvin]

Well AC dangerous than DC as it has an attractive tendency rather than DC which has a repulsive one So a guy fingering over an ac circuit is more likely to stick with it rather than DC in which he'l be thrown away. :D

[toddrharrison]

I'm going to say DC is more dangerous to work with because once you touch something with DC your muscles will contract and stay contracted making it impossible for you or others to remove you from the power. With AC your muscles would be pulsing on and off giving your reflexes a chance to pull away or somebody to knock you off the power before even more permanent damage is inflicted.

[mjlorton]

@toddrharrison ;-) I'll say no more. Will discuss in next video.

[orbiter8]

Ok... I'll bite :) IMHO I never consider either AC or DC more dangerous than one another. Given the right circumstances and conditions, both AC and DC can kill you, even at low voltage and current.

Overall AC is considered more dangerous though as it has the greater chance of forcing the heart's natural pacemaker into fibrillation.

[samgab]

AC vs DC? It depends a great deal on the CURRENT and the VOLTAGE. A 1mV, 1mA AC power source is relatively safe, whereas a 10KV 50A DC source would be very dangerous. And a 1mV, 1mA DC power source would be relatively safe, and vice versa. But at standard 110V or 240V 50 or 60 Hz, AC can cause ventricular fibrillation at fairly low currents (~60mA). DC can also cause this, at higher, but still relatively low currents (~500mA). High Voltage, and even more so High Current, are the key dangers.

[mjlorton]

@samgab Aaah...good answer Sam...will review in the next video.

[samgab]

Nice simple instructional video. You should be a teacher! Do you teach your little daughter about electricity and DMMs yet?

Couple of points: 16:28 and 16:32 , should be "1.191 Volts". Just a small slip of the tongue, and I'm sure everyone knows it's what you meant. An AA cell reading 1.91V would be a problem! Oh, and a pedantic little point; although AA cells are commonly referred to as "batteries", a battery is more than one cell. An individual cell is just a cell, and not a battery. Thanks!

[mjlorton]

@samgab Thanks good man! I picked up some of those just before I posted it but I'll go and make annotations now. Cheers.

[mjlorton]

@samgab Thanks, annotations done! Now then...teaching my five year old daughter about DMMs...Mmmm not quite yet...there are a few other challenges / lessons to teach at this point LOL! But she does know about solar power (surprise, surprise!) and that it's important to recycle!

Thanks again for being pedantic.

[samgab]

@mjlorton lol Good stuff! I always feel silly telling people about cells vs batteries, but I can't help myself!

[samhell4]

if i remember right dc power can stop you r heart because it run @ 60hrz much i may be wrong there

[mjlorton]

@samhell4 Thanks for posting an answer, I will cover this in the next video.

[Colin1875]

Are there any types of gloves that you can where to protect your self?

[mjlorton]

@Colin1875 Very good question....I have been trying to find good gloves myself. Let's see if others have input on this.

[keenantims]

I would recommend using the clips that attach directly to your probe tips (or banana->clip leads) instead of just clipping to the probes. Much safer, though sometimes a bit awkward.

[mjlorton]

@keenantims Very good point...I will annotate / cover that off in the next video.

[franciscool1000]

dc power because dc current does elecrolysis of body fluids.

[mjlorton]

@franciscool1000 Thanks for posting, we'll cover the answer in the next video.