Inrush current limiters are required for soft starting of electrical equipment, such as transformers or electric motors. These are required because when such equipment is switched on it draws very high currents to charge up the capacitors. These high starting currents must initially be limited by means of resistors, so that no damage is done to the equipment. Inrush current limitation starts as soon as voltage is applied to the equipment. After the voltage has been switched off, the inrush current limiters are once again ready for operation. Soft starting is also necessary for portable electric power tools such as drills and angle grinders, in order to protect the user.