The Constant Voltage Drop Model

• We utilize a vertical straight line to approximate the fast growing part of the exponential curve, as indicated in the diagram.

(i)         Diode current will stay at zero till the knee voltage is reached.

(ii)        Once the applied voltage attain the value of V_k , the diode turns on & the forward conduction take place.

(iii)  so long as the diode conducting, the value of V_F is about equal to v_K. In other terms the value of V_F is supposed to be 0.7volts regardless of the value of I_F.