The Effect of the Forward Voltage Drop on Circuit Analysis

To demonstrate this effect let this circuit,

According to the KVL eq, the total of the component voltages in the circuit ought to be equivalent to the applied voltage .                     

                                    Formula V_s = V_F + V_R

                                    Here,   V_s = voltage of source

                                                V_F = forward voltage across the diode

                                                V_R = voltage drop across I ohm resistance

if we let diode is a silicon therefore, V_F =0.7 volts and arrange this eq for V_R then

                                                            V_R = V_s - 0.7V

            By ohms law we can say

                                                             I_T  = V_R / R

                                    Substituting the value of V_R from this equation

                                                             I_T = V_s - 0.7/R₁

                                                substituting the value of R₁ we get

                                                                 =  5 - 0.7/1= 4.3A

If we let this diode to be ideal than no voltage drop will take place across it and we will obtain

                                                            V_s = V_R

                                                            V_F = 0

                                                             I_T = 5mA