Why are there different types of coils?

[DARK0717]

i wanna focus on the simple wind of coil vs a coil with primary and secondary windings.
Dont a normal wound coil already increase the voltage?
What is the principle of step up coils with primary and secondary windings?(this isnt much clear to me)

Why should I use the other over the other?
Easiest DIY step up coil? goal voltage is probably atleast enough volts to make a spark gap

Additional: since voltage is means pressure, meaning, can I increase voltage to discharge much faster or it still depends on the discharge rate of the source? (think of it like pouring tons of pebbles on a really fast conveyor belt)

 

[Sensei]

Coil can increase or decrease voltage between primary (input) and secondary winding (output). How much it increases or decreases depends on quantity of windings on either side.

e.g. you can make transformer which creates both 5 V and 12 V at the same time, by using different quantity of windings, from the same input power source.

Power (P_src = I_src * U_src) of input is slightly higher than sum of power(s) of output(s) (P_dst = I_dst * U_dst). Lost energy is released as heat on transformer. If you will have no load element on output, you can still measure some tiny lost of power on the input. Easily checkable by plugging transformer without any output load to wattage meter. It should show very low current ~mA/uA or so. Or by measuring increase of temperature of transformer that does not have any load. Therefore people who want to decrease power consumption in the house use power strips with button and shut it down at once when the all devices plugged to it are not used e.g. over night.

We can make equation like:

P_src = P_dst + P_lost

I_src * U_src = I_dst * U_{dst +} P_lost

or if there are multiple outputs:

I_src * U_src = ( I_dst1 * U_dst1 + I_dst2 * U_dst2 ) + P_lost

 

Increasing input voltage above coil parameters will lead to overheating and might result in damage of wire in the windings not prepared to flow of current with much higher amount than expected. Typical way computer power supply unit ends up life is overheating of transformer caused by failure of the fan which cools it down. Damaged transformer can give too large current or voltage (shorted damaged windings = different quantity of windings) to the rest of computer hardware, and motherboard, CPU or other peripherals might be damaged in consequence.

Edited April 7, 2020 by Sensei