2 suggests still another function for the transformer. For maximum transfer of energy from an emf device to a resistive load, the resistance of the emf device and the resistance of the load must be equal. The same relation holds for accircuits except that the impedance (rather than just the resistance) of the generator must be matched to that of the load. Often this condition is not met. For example, in a music-playing system, the amplifier has high impedance and the speaker set has low impedance. We can match the impedances of the two devices by coupling them through a transformer with a suitable turns ratio.
: An alternating-current emf device has a smaller resistance than that of the resistive load; to increase the transfer of-energy from the device to the load, a transformer will be connected between the two. (a) Should N, be greater than or less than N,.?
(b) Will that make it a step-up or step-down transformer?