eli5 Why are 110v transformers so physically heavy?

Question

For instance, a computer inputs 230v and is capable of splitting into various lower voltages and remains light?

In: 0

Answer 1

A transformer will have two or more “windings” of copper wire around an iron core. In simple terms, the ratio of the windings on the “primary” side- where power is applied- to the “secondary” side, where power is taken out, will determine whether the voltage goes up or down. If the secondary has fewer windings than the primary it provides lower voltage but can drive higher currents, and if it has more windings, higher voltage at lower current.

If a transformer is large and/or heavy it’s probably intended for either very high voltage on its output or high current on the output with a lower voltage- microwave oven transformers are an example of this, and do both at once.

A large transformer is going to be heavy simply because it has a solid iron core and lots of copper wire around it- if it’s handling large voltages and/or current, that’s necessary to keep it from burning up from the heat it generates.

A computer power supply will be a bit smaller, but will usually have a transformer in it- just not a really massive one like in a microwave. So they weigh a lot less.

Edit: If you specifically mean why a 110v transformer is heavier than a 240v one, it could be that the 110v transformer is intended to generate similar power at its output, but because at lower voltage that means more current (ohm’s law), it needs to be heavier to handle that higher current load.