To plot the VI characteristics of a pn junction diode.
EDWin Components Used
Number of components required
The circuit diagram to plot the VI characteristics of a pn
junction diode is shown. Applying a positive potential to the anode and a negative
potential to the cathode of the pn junction diode establishes a forward bias
condition on the diode. As the applied potential is increased the depletion region width
decrease and conduction of electron increase. In general the characteristics of the
semiconductor diode can be defined by the equation
Where IS =
reverse saturation current
k=11600/h with h
=1 for Ge and 2 for Si.
TK = Temperature in ° Kelvin
TC = Temperature in ° Centigrade
VD = Applied potential
ID = Diode current
For positive values of VD, ID is
positive and increases exponentially. At VD=0, ID is
also zero (ref: equation). For negative values of VD, Id = -Is which is a horizontal line. This
explains the VI characteristics of pn junction diode.
EDWinXP Project Explorer -> Page(MAINPAGE) -> Edit Page: The
circuit diagram is drawn in the schematic editor page by loading components from the library. Wiring and proper net
assignment has been made. The resistor R is assigned a proper value.
EDWinXP ->Preferences -> Mixed Mode Simulator: The circuit is preprocessed.
The VI characteristics may be obtained by performing DC Sweep Analysis. The current
waveform marker is placed at the anode of the diode. The sweep parameter (voltage) for
input source is set in the Analysis window. The applied voltage is swept from an initial
value of 0 to final value of 1V in steps of 1mV. To get VI characteristics, the
currents corresponding to varying input voltages are noted. The VI graph is
observed in the Waveform Viewer.
The output waveform may be observed in the waveform viewer