Isolation Transformers For Dummies

Everything you wanted to know about isolation transformers but were afraid to ask.

[dscarbrough]

Dave, Dave here. I so enjoyed this. I had a very similar experience with an old wooden Crosley radio with bakelite knobs when I was 6 yrs old. Scared the **** out of me. I have since learned safe experimentation techniques. I found this vid after looking for iso's for passive loop antennas for HF SWL. Your explanation here makes so much sense and I really appreciate it. Very informative. TY and best regards to you in BC from the vast wasteland that is South Dakota. ;-)

[dtravis]

Dave, Thanks for posting this. Many (including me when i was a young kid) thought a Variac was an Isolation Transformer which of course it's not. Thanks again. Outstanding video like always.

[stackoverflow]

If you cannot explain something in simple terms, you don't understand it. -Richard Feynman.

You did an excellent job!

[garthhowe]

What an excellent description. I use an isolation transformer, but never really thought too much about the details. Thank you!

[zulumax]

Many oscilloscope probes get blown apart when the ground wire connects to a hot TV or radio chassis. You must use an isolation transformer.

[olleinsulander]

Great video. Getting ready to buy or build an isolation transformer and your video is explaining the phenomenons involved in an excellent way. It stands out from the ones I´ve watched previously. Lovely story from the formative years! Greetings from Sweden

[johncoops]

In the 1960's I had an old STC valve radio which zapped me from a Live chassis. Here in Australia we have 240V AC, so the jolt was literally enough to "throw me" about 10 feet. I was about 7 years old as well, and dripping wet after getting out of the pool - .I certainly wasn't expecting such a thing, and my arm and chest hurt for a long time afterwards!

[ronrhoades]

I love it at 1:18 when you make contact to the external test ground and meter probe. Stay safe.

[careycraig]

Excellent Presentation! The importance of this information can not be over stated.

[cf]

in EU, at least in my country, we do not have any guaranty which side of the plug is the hot. your plug can be plugged into the 220 main any way, both the plug and the socket is fully symmetrical.

[voltvids]

That's a variac and they are not isolated. I have an isolation travafirner ahead of my variac.
On a true isolation travafirner there is no connection between mains and ground so measuring either the hot or neutral should in a perfect world measure 0.
I will do a short new update to show this operation.

[billbaden]

If you need a light way out in the back forty and don't have a long extension cord but do have a long spool of single wire you can drive a ground rod at the location and use that for nuetral. The supply voltage will depend on the resistance between the location ground rod and the main service panel ground

[franzliszt]

I watched many, many isolation transformer vids, and this one is the best.

[ja_adam_]

hey, i'm just struggling to understand how if you touch live (Hot) and youre touchign a metal tap for example, why you wont get a shock? as you still have a path to earth?

[rickclink]

Thanks Dave for the video. I work on audio equipment and figured transformer powered preamps were isolated from having a hot chassis. I measured my new dso’s bnc sheild to the preamps chassis. Wow 50vac. This preamp transformer has a grounded center tap secondary. Could this 50vac be induction induced? I am holding no one responsible for any answer I receive. Thank you

[balisticsquirel]

Would you say that the lesser ground (screw driver) has an increased resistance in the circuit when it's used? Greater resistance then leading to less flow of charge? Or is there some other characteristic than resistance? Could we vary power consumption of some device by varying the ground it uses rather than adding resistance (variable resistors) into the circuit, rather than burning off the 'excess' power when we want to 'dim' the device?

[surgingcircuits]

That was very helpful. Thx! Best Explanation I've Seen.

[chillidogkev]

On an isolation transformer that isn't really an isolation transformer because the neutral is bonded from the input to the output as per your diagram...what's the point such a device? Why would the manufacturer do that when it would work perfectly without the bonded neutral AND offer an isolated output?!?

[Boffin]

A bit confused . Around 11:15 you talk about the incoming power neutral carrying the entire load ??? Won't the neutral at the premises carry that load via the earth bonding to ground at the premises??

[Friendroid]

I have a philco radio (46-200 something) and a Perpetuum Ebner record player I would like to fix. I wont put my hands on them before I get myself an isolation transformer, because both have a hot chassis.