Diode equivalent circuits

Posted by AJ × 23:39

• An equivalent circuit is a combination of elements properly chosen to best represent

the actual terminal characteristics of a device, system or such a particular operating

region.

• Then device symbol can be replaced with the equivalent circuit which makes the

analysis of the circuit easy and straight forward.

Piece wise linear equivalent circuit

One technique for obtaining equivalent circuit is to approximate the characteristics of the

device by straight line segments

• Rd defines the resistance level of the device when it is in the ON state.

• Ideal diode is included to establish that there is only one direction of conduction

through the device.

• Since silicon semiconductor diode does not conduct until VD of 0.7V is reached, a

battery opposing the conduction direction is included.

Simplified equivalent circuit

• In most of the applications, resistance rav is very small in comparison to the other

elements of the network.

• Removal of this rav from the network makes a simplified equivalent circuit.

• And an ideal diode will start conduction for zero applied voltage.

All Syllabus