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Coil wire?

hantto

Member
Correct me if i'm wrong, but isn't coil wire normal copper wire with a protective lack film on it?
 

kinjalgp

Active Member
Thats true Hantto! :)
Enamel is applied on copper wire so that when it is wound, the adjacent windings do no get short circuited.
 

kinjalgp

Active Member
Since copper is best known and affordable conductor, it is the most widely used for inductors. Other metals will give unnecessary resistance to inductors which will degrade its performance.
 

hantto

Member
It's so very hard to find a ferite rod anywhere.. so that i was wondering: can't one do a air core coil that is as good as a ferite rod core, but with more windings?
 

kinjalgp

Active Member
It all depends on where you are going to use your inductor. In applications like AM Radio Ferrite core is a must. Ferrite improves the Q-factor (Quality factor) of the coil.
Air-core can also work in some cases.
Let me know your application
 

kinjalgp

Active Member
If you find it difficult to get the ferrite rod use other oscillators which do-not use inductors. One such is astable oscillator. Have a look at ths stun gun project at http://www.electro-tech-online.com/threads/simple-lie-detector.40/.
Instead of audio transformer mentioned in the project you can use normal iron core transformers and obtain high voltage to drive tube lights. One thing to be noted here is that if the frequency of the oscillator is high, the losses in iron-core transformer will be high as compared to ferrite core which will drain you battery faster (not very fast but backup time will be less)
 

hantto

Member
So that i can't use an air coil... OK

Can one connect a normal transformer backwards (give 12V to a 12V/230V transformer) and get 230 out of the other end?
 

mechie

New Member
Backward Mains Transformer

A mains transformer will work fine connected backwards -BUT-

The little oscillator driving the transformer will only be capable of a few-hundred mA, trying to use a transformer with a 10A secondary will provide such a low impedance as to completely short the output.
You need to choose logically - a small transformer as used to power old cassette recorders or tiny radios would be best - a 9v secondary capable of 100mA ? or 50mA ?

Experiment to find something that works (240v to 3v tx backwards with 9v in could give 600v out ??? [yes you are pushing the insulation beyond its design] )

Don't expect the full voltage out - you will have losses.
Don't expect more power out than you put in (100mA to a 24/1 ratio transformer will give 4mA out ???)
 

kinjalgp

Active Member
Mechie, How about a Push-Pull Transistor Configuration for Centre-Tap transformer or Simple Transistor as a Switch for 2-terminal transformer? It won't short the output of oscillator and will effeciently drive the transformer upto many Amperes. And if MOSFETs are used it will work out at its best giving very high input impedance without loading the oscillator.
What do you think.
 

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