How many times does a copper wire have to go around the input side of a transformer to get the necessary amount of magnetism from 110 volts?How thick does the wire around the transformer have to be if the input it 110 volts? Can it be one wire as thin as a garbage bag tie, or does it need to be as thick as the original wire, but stripped and coiled around the transformer core?
magnetism or magnetic field does not have a direct relationship with voltage. In a basic transformer, there are two coils. If your source is 110 volts on the input coil, and there are 100 turns of wire in the input coil and 200 turns in the output coil, then the voltage across the output coil will be 220 volts. This is because the turns ratio, (number of turns in output coil divided by number of turns of input coil) 200 / 100 2. And output voltage is equal to input voltage, multiplied by the turns ratio. Therefore, considering a second transformer with an input coil of 50 turns and output coil of 100 turns, the turns ration is still 100 / 50 2. Therefore if this transformer were connected to the same 110 volt source, the output 110 * 100 / 50 220 volts, same as for the first transformer. In a practical sense, many common small power transformers are designed with one turn of wire per volt. But this design also reflects the mass of silicon steel that is used in the design of the core which is also a very important part of the transformer design.
As stated in another answer, the basic transformer equation is: E 4.44 X f X N X Ac X B E is the applied RMS voltage f is the frequency (Hz) N is the number of turns Ac is the core area (square meters) B is the maximum flux density (Webers per square meter also kknown as Teslas) If the design is for 120 volts at 60 Hz and 1 Tesla, the required number of turns would be about 0.5 divided by the core area. PS The voltage has nothing to do with the thickness of the wire. Wire thickness is determined by current, the desired internal voltage drop in the wire resistance and the tolerable temperature due to internal losses. Magnet wire is used. It has very thin insulation to use the minimum space and allow heat to be more easily conducted out of the coil. The wire can not be stripped bare.
The number of turns required is NErms/(1.414 pi f B Ac) where Erms is the primary RMS voltage, f is the frequency, B is the peak flux density which is a function of the material, and Ac is the cross sectional area of the core. The current density in the wire and the physical size of the transformer determine the temperature rise due to I^2 R (and core losses). It should be less than 400 amps/cm^2.
