you all my thanks and this is now my fav forum for electronics I remember I asked this on another couple forums online years back and got no reply so thanks to you all I love how informed everyone is and thank you for all the help I might try and figure out a project to use it on if anyone has any ideas I would love to hear them and would make a new thread on that project when I do have a project in mind until then thanks everyone you rock

 

thank you for your concern i would agree and if i were like most everyone i have ever known i would long ago have likely elecrocuted my self to death as luck would have it i was bestowed a great gift that very few belive untill i show them in person i for resond unknownto my self boast an electrical resistance ...


... i wonder if there is more people who share this gift as well i know there must but i havent ran into any yet

according to this yes.

 

Believe me, you have no special gift that makes you more resistant to electrical discharge.

Welcome to AAC!
If one of these days we do not hear from you, may you rest in peace.

 

Before that happens, to my list.

 

Autotransformer didn't even enter my thoughts. I know what they are but I don't think I ever actually came across one. Very low on my list of possibilities but will try to remember next time.

Actually, you've come across them a lot and just didn't know it. Most automotive ignition coils are autotransformers -- at least the old style ones are, I don't know about current ignition systems, but it seems likely that they still are.

 

There is nothing about the step-up transformer/spark coil that is compatible with mains level voltages. It is not designed for anything close to a large duty cycle, but rather to be triggered to generate a short burst of high voltage pulses to zap a mouse. It would also be fairly effective in a system to chase squirrels out of a bird feeder. 25 years ago I designed a system for a client to do just that. The squirrel jumped off and ran away and never came back. It did need to be used to train a few other ones, but the result was that only birds visited the bird feeder. (the safety police here should observe that I did not describe any details of that device at all, thus no rule violation)
The only other use I can think of would be as a magnetic pickup for some sort of musical device. Use 4 of them for pickups in a bass guitar, for instance.

 

Regarding that one post that is a run-on jumble. I am not aware of what sort of device you were using, but it is really not suitable for use here. And there are keywords that insert punctuation and paragraphs.
More important by far is putting thought into the comments being offered. Providing advice is a serious business, and so it is important to qualify guesses as just that, and what can lead towards a useful conclusion is asking questions to get the information needed to actually know what is needed.
It looks like that dictated post has been removed. OK on that.

 

Believe me, you have no special gift that makes you more resistant to electrical discharge.

Welcome to AAC!
If one of these days we do not hear from you, may you rest in peace.

It will never seas to amaze me that when presented with contrary evidence people will out right reject something.

 

It's the VooDoo principle. Magic beats reality every time. Or so they think until reality bites them.

 

Couple things: First, yes, I agree with "Auto Transformer". Second, you may be thinking about a traditional transformer where the primary side is isolated (electrically) from the secondary side. Such transformers are used to change one useful voltage into another useful voltage. But with auto-transformers, they're primarily designed for generation of high voltages.

The last thing I want to say:

Unfortunately computers do not fully grasp the whole concept of grammar. And I use dictation to type, so everything is one very long run-on sentence. And even with Grammarly it only does so much to correct this. And I'm not about to pay what they are asking for the program to fix it, so this is the way it will be. Typing with my thumbs on my cellphone renders much worse results then (than) that i assure you of that.

is that when I use "Speech to Text", when I reach a point in my statement that requires an apostrophe I state the word "apostrophe", and it inserts one. Same with "period". It inserts the little dot at the end of the sentence. And the next sentence is automatically started with a capitol letter. Give it a try. (period). Also, I edited (added caps and punctuation to your quoted message).

 

But with auto-transformers, they're primarily designed for generation of high voltages.

Definitely not true.
Autotransformers made by Variac are primarily intended to LOWER the AC mains supply voltage.

 

On the science of a three-legged autotransformer vs a four-legged isolation transformer, there is little difference between the two.
The only difference is that the "primary" and "secondary" windings share a common node in an autotransformer.

 

Definitely not true.

Perhaps the word "Autotransformer" is not the correct word. However, what the thread starter (TS) is in possession of is a transformer the likes of which are found in "Inductive Ignition Systems" in older cars. Ignition coils - so-to-say.

I've owned a number of autotransformers. The truest nature of the beast is a transformer with an adjustable center tap. Like a very large potentiometer - but done with coil windings. I have a few laying around. Perhaps I'll grab one and take a picture of it and post it.

 

This is one of the several autotransformers I have. It consists of a wound coil going from end to end where AC power is applied. Using one of the two ends and the center wiper you can select different voltages in a (nearly) infinite percentage of the total applied voltage.

 

Be careful with knowing the difference between a power rheostat and an autotransformer.
It is not always easy to tell the difference.

This a power rheostat, used for DC or AC:


This is a variable autotransformer, used for AC only:

 

@MrChips The unit I have (many of them) consists of a feroresonant isolation transformer connected directly to the two inputs of the device I've pictured. Adjusting the knob selects a varying output from 0% to 100% of the isolation transformer voltage. Perhaps what I have IS a rheostat. What's the difference?

 

A rheostat is resistive. It will work for both DC and AC. It will consume power and get hot. It is basically a voltage divider and works on Ohm's Law. You can lower the voltage. You cannot go higher than the input voltage.

A variable auto transformer is inductive and is based on electric and magnetic fields. It will work for AC only. If you attempt to apply DC voltage something is going to blow.
An autotransformer does not consume power as it is almost 100% efficient in transferring AC VA from the source to the load.
You can have output AC voltage that can be lower or higher than the input AC voltage.

 

You can have output AC voltage that can be lower or higher than the input AC voltage.

I have a rheostat.

[edit] as per @MrChips statement I have an autotransformer. A magnet will not stick to ceramics. The magnet I used was difficult pulling it away from the core.

 

Perhaps the word "Autotransformer" is not the correct word. However, what the thread starter (TS) is in possession of is a transformer the likes of which are found in "Inductive Ignition Systems" in older cars. Ignition coils - so-to-say.

I've owned a number of autotransformers. The truest nature of the beast is a transformer with an adjustable center tap. Like a very large potentiometer - but done with coil windings. I have a few laying around. Perhaps I'll grab one and take a picture of it and post it.

My favorite autotransformer was one that I used to drop 125 volts down to 110 volts for an older piece of equipment. It has one winding with a tap at the 110 volt point. It can also be used to deliver 12 volts AC, but not isolated from the mains. I have seen that kind used to power 12 volt high-intensity lights. Not especially safe, but cheaper than a separate winding.

 

But with auto-transformers, they're primarily designed for generation of high voltages.

I don't know that any kind of a blanket statement can be made in this regard. Autotransformers come in all kinds of different types for different purposes. It could probably be argued that, in sheer number, automotive ignition coils are the most numerous and therefore this would be true. They they are also common in universal 230/115 power supplies and there they can either step up or step down and there may be more of those than there are automobiles. Also, a very common application for autotransformers are for adjusting AC power either up or down, either for voltage regulation or for tolerance testing. This is done both on the test-bench scale and the industrial power distribution scale.