Question

A diode is often connected in parallel with a motor or other inductive loads. Why?

Answer 1

In an ideal case when the switch is off or the power supply is disconnected the motor becomes idle i.e no voltage geneartion due to the inductance of the coil

However, in an actual circuit due to the inductance of the motor current will to continue to flow immediately after the motor turns OFF, causing the voltage to swing to below the ground level at the negative (–) terminal and above the supply voltage level at the positive (+) terminal. This can result in the generated voltage of the motor exceeding the supply voltage. To prevent this, when using a power transistor as the switch it is necessary to connect a power diode in parallel in order to suppress (clamp) the generated voltage using the forward voltage of the diode.