• Reverse Bias: When the diode cathode is connected to the positive terminal of the power supply and the diode anode is connected to the negative terminal, the PN junction barrier increases, and almost all current is blocked, with only a very small leakage current. • Reverse Bias: When the diode cathode is connected to the positive terminal of the power supply and the diode anode is connected to the negative terminal, the PN junction barrier increases, and almost all current is blocked, with only a very small leakage current. The diode polarity refers to the installation orientation of the two leads of a diode, with one being the anode (positive) and the other the cathode (negative). The diode direction directly determines the way current flows within the device and also decides whether the circuit can operate normally. Reverse (Backward) Voltage - which causes an increase in the potential barrier of the junction, and lowers the possibility for an electron to cross the junction to the other side. So instead of the positive current going into the diode, it just escapes. A diode is simply made from 2 pieces of semiconductor material (or likely, one piece with 2 different regions). These are usually called the n doped region and the p doped region. The p-n junction diode allows electric current in forward bias condition whereas it blocks electric current in reverse bias condition.