Re: inductive kick
the voltage equation of a inductor is V=L(di/dt).... so the property of the inductor is to keep the current through it constant.....
but when we switch off the supply across the inductor the voltage across the inductor spikes up due to the sudden change in current and due to the property of the inductor it tries to keep the current constant and hence pulls more charge which leads to the voltage spiking up till more.... this is called inductive kickback or inductive kick....
it is very dangerous for semiconductor circuits and hence a diode is used across it in the opposite direction of normal current flow to suppress inductive kickback...