2.
<ul><li>Transformer: </li></ul><ul><li>A Transformer is a device that transforms power from one circuit to other circuit without change in frequency. </li></ul><ul><li>It is a static device and all currents and voltages are AC </li></ul>

3.
Transformers - used to supply the different voltage requirements of the appliances we use from the mains supply. Door Bell (6V) Step-Up Transformer Step-Down Transformer Main Supply (230V) Example: Television Set (>1k V)

4.
06/15/11 Primary Coil - Connected to electrical supply Secondary Coil - Connected to electrical load (eg. Lamp, door bell, television set) The structure of transformer: ~ Supply ~ Electrical Load Primary Coil Secondary Coil Soft Iron Core

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Transformers Types: <ul><li>Step-Up Transformer - Lesser turns in primary </li></ul><ul><li>Step-Down Transformer - Lesser turns in Secondary </li></ul>Primary Coil Secondary Coil Load Supply Secondary Coil Primary Coil Load Supply

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<ul><li>Working principle </li></ul><ul><li>When the switch is closed: </li></ul><ul><li>Current in primary coil increases </li></ul><ul><li>Creates increasing magnetic field in primary coil </li></ul><ul><li>Induces voltage in secondary coil </li></ul><ul><li>Lamp lights up </li></ul>Primary Coil Secondary Coil Soft Iron Core ac supply

7.
<ul><li>There are two general types of transformers </li></ul><ul><li>Core type transformer </li></ul><ul><li>Shell type transformer </li></ul><ul><li>These two differ by the manner in which the windings are wound around the magnetic core. </li></ul><ul><li>In order to reduce the eddy current losses, the core is laminated. </li></ul><ul><li>In order to reduce the core losses, transformers have their magnetic core made from cold-rolled grain-oriented sheet steel (C.R.G.O). </li></ul>Transformer Construction:

8.
Transformer Construction: Core Type Transformer:

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Transformer Construction: Shell Type Transformer:

10.
<ul><li>There are two types of windings employed for transformers. </li></ul><ul><li>concentric coils. </li></ul><ul><li>Interleaved coils. </li></ul><ul><li>The concentric coils are used for core-type transformers and interleaved coils for shell-type transformers </li></ul>Transformer Construction: