Diode circuits, Electrical Engineering

Diode Circuits:

Prob. (a) Draw the piecewise linear volt ampere characteristic of a p n diode. What are the circuit models for the ON state and the OFF state.

(b) Determine V0, I1, IS, and ID2 for parallel diode configuration of fig.

Sol. (a) Piecewise linear Equivalent circuit

One technique for obtaining an equivalent circuit for a diode is to approximate the characteristics of the device by straight line segments. The resulting equivalent circuit is naturally called the piecewise linear equivalent circuit. It should be obvious from fig. (1) that the straight line segments do not result in an expect duplication of the actual characteristics, especially in the knee region. However, the resulting segments are sufficiently close to the actual curve to establish an equivalent circuit that will provide an excellent first approximation to the actual behavior of the device, for the sloping section of the equivalence the average ac resistance is the resistance level appearing in the equivalent circuit of fig. (2) next to the actual device. It defines the resistance level of the device when it is in the "on" state. The ideal diode is included to establish that there is only one direction of conduction through the device, and a reverse bias condition will result in the open circuit state for the device. Since a silicon semiconductor diode does not reach the conduction state until VD reaches 0.7 V with a forward bias, a battery VT opposing the conduction direction must appear in the equivalent circuit as shown in fig. (2). The battery simply specifies that the voltage across the device must be greater than the threshold battery voltage before conduction through the device in the direction dictated by the ideal diode can be established. When conduction is established the resistance of the resistance of the diode will be the specified value of r av. Here VT in the equivalent circuit is not an independent voltage source. If a voltmeter is placed across an isolated diode on the top of a lab bench, a reading of 0.7 V will not be obtained. The battery simply represents the horizontal offset of the characteristics that must be exceeded to establish conduction.

Posted Date: 2/8/2013 2:52:11 AM | Location : United States

Related Discussions:- Diode circuits, Assignment Help, Ask Question on Diode circuits, Get Answer, Expert's Help, Diode circuits Discussions

Write discussion on Diode circuits
Your posts are moderated
Related Questions
Name the various magnetically hard alloys. Several of the magnetically hard materials are rare earth carbon steel, cobalt, tungsten steel, alnico, hard ferrites and cobalt stee

can you help with my electronic principle assignment

Q. Explain the construction of depletion MOSFET? A slab of p-type material is formed from a silicon base and it is referred to as the substrate. It is the foundation upon which

Discuss mode -2 (bi-directional mode) of 8255 (Programmable Peripheral Interface). Only permitted with port A. Bi-directional bus data used for interfacing two computers and GP

Zener Diode A Zener diode is a sort of diode that allows current not only in the forward direction such as a normal diode, but as well in the reverse direction if the voltage

The field winding of a 200 V d.c. machine has a resistance of 20? and an inductance of 500mH. Calculate: (a)  The time constant of the field winding (b)  The value of curr

role of electrical engineer in disaster management

Q. Explain Steady-State Error of Linear Systems? If the steady-state response of the output does not agree exactly with the steady state of the input, the system is said to hav

To design a VI that can be used to show how the voltage falls across a resistor in a simple CR circuit when excited by a step function. The title of the VI will be Capacitor Res

Ask question #Minimukkgkmm 100 words accepted#