As shown in Figure 4.2, the coil connected to the ac source is called the primary winding or simply the primary.
The primary current sets up the flux, ~ in the core, which varies periodically both in magnitude and direction. This flux
links the second coil, called the secondary winding or simply the secondary. As the flu) is pulsating ; therefore, it
induces a voltage in the secondary by electromagnetic induction in accordance with Faraday's law. Thus the primary receives
its power from the source while the secondary supplies this power to a load. This action is known as transformer action.
Note : To transmit a given amount of energy (or equivalently, power P = VI ), less current is required at a high voltage
than at a low voltage. This means that energy may be transmitted with less 1 2 R or line loss when high transmission voltages
are used.
