First of all, electricity is very dangerous for human beings, because a lot of people die of electrocution, so how to protect the safety of electricity users is very important in this era of electricity. Resistance is placed behind capacitance in which have certain security considerations, we use the electrical appliances off when the voltage capacitance and not fully released, so this time if the human to touch the plug is the risk of electric shock, so if all these voltage light can be very good avoid such risks, then the resistance is played such a role, it gives the excess electricity is clean.