summary
● A transformer consists of two coils: a primary winding and a secondary winding.
● An AC voltage is put across the primary winding, inducing a voltage in the secondary winding.
● Transformers allow an AC signal to be transferred from one circuit to another.
● Transformers allow stepping up, stepping down, or passing the signal unchanged.
● Transformers are designed to operate at certain frequencies.
● The turns ratio determines whether a transformer is used to step up, step down, or pass voltage unchanged.
● The ratio of secondary to primary voltage is equal
to the ratio of secondary to primary turns.
● A transformer that produces a secondary voltage greater than its primary voltage is called a step-up transformer.
● The turns ratio of a step-up transformer is always greater than 1.
● A transformer that produces a secondary voltage less than its primary voltage is called a step-down transformer.
● The turns ratio of a step-down transformer is always less than 1.
● The amount the voltage is stepped up or down is determined by the turns ratio.
● Transformer applications include impedance matching, phase shifting, isolation, blocking DC while passing AC, and producing several signals at different voltage levels.
● An isolation transformer passes the signal unchanged.
● An isolation transformer is used to prevent electric shocks.
● An autotransformer is used to step up or step down voltage.
● An autotransformer is a special transformer that does not provide isolation.