Transformer is static device. two or more stationary electrical circuit mutually linked by magnetic circuit. assumptions of ideal transformer: 1. there are no losses. 2. whole magnetic flux constant no leakage. 3. permeability of core is infinite.
In step up votlage, Output votlage > Input votlage Output current < Input current
In step down transformer Output votlage < Input votlage Output current > Input current. Power and frequency remains almost constant in stepup or stepdown transformer.
EXAMIANS