What is the difference between a tranformer and rectifer?

Answer 1

A rectifier is used to change ac to dc, but a transformer is used to convert the ac voltage, from ac at certain valtage and current, to another ac voltage with another voltage and current.

A rectifier, is either a semiconductor device or a vacuum tube, with two main electrodes (also known as a diode for this reason). It will only pass current of one polarity, blocking current when it is reversed. Putting an AC current through it will cause bursts of current to flow in one direction, forming interrupted DC.

A transformer consists of two separate coils of copper wire, wound around the same former and soft iron core.

An AC signal on one coil, will cause another to be produced in the second.

By altering the number of turns of wire used in each coil, you can select whether the voltage is more or less than the input.

If the voltage is increased, the current available becomes less, and vice versa.