By using the experimental set up (the designed electric circle), the voltage was varied in steps from 0 V - 0.6 V by using a voltmeter. At each voltage value the current value was recorded by using an ameter. The values of the voltage (V) and current (I) are tabulated in tables in case of forward bias PN juction. The procedure is repeated for the reverse bias PN juction and the results and measurements are tabulated in the results’ table. The data obtained from the experimental set up are plotted in I-V graph. From the graph the I-V characterstics of the semiconductor material under investigation are obtained.The knee voltage (V knee) is determined from the plotted I-V graph”.