Step up input AC

Step down input AC

Step up AC from amplifier

Step down AC from amplifier

Auto transformer

Static transformer

Ring core type transformer

Ferrite core type transformer

Self-induction principle

Fall in potential principle

Ferro-resonant principle

Mutual induction principle

Step up transformer

Step down transformer

Torodial autotransformer

Constant voltage transformer

Ammeter

Voltmeter

Ohmmeter

Multimeter