Diode is a basic electronics device that is used for protection purpose. A diode has two nodes; anode (+) and cathode (-). When we apply voltage at anode (+) higher than the cathode (-), the diode acts as short circuit. It is called “forward bias”. On the contrary, when the voltage at anode (+) is lower than the cathode (-), it is called “reversed bias” and the diode acts as open circuit. Fig. 4 shows symbol and diode figure[4].