Practical Model
In practice we search that there is a voltage drop of approximate 0.7 V across the diode (silicon; germanium= 0.3 V) while this is forward biased, and therefore it is frequently useful to include this voltage drop in circuit analysis. hence, the practical model is the ideal model along the addition of a voltage source in the forward bias model. Diagram C indicate the practical model characteristic. The practical model is shown in diagram C-a.
Diagram C: Practical diode characteristic.
Diagram C_a: Practical diode model.
The resultant model simply says that a forward conducting diode show a constant voltage drop VD. Usually the value of VD is taken to be like 0.7 volts in case of silicon diode. The constant voltage drop model may be showed by the correspondent model indicated in the diagram.
