bhathi123
Newbie level 5
Consider these equations for diode rectifier;
I(V) = Is(e^(alpha*V) -1) -----------(1)
Let diode voltage be V=Vo+v --------------(2)
Then, Using taylor series for the diode current I(V) [equation (1)] we have;
; where Io=I(Vo)
; where Gd is the dynamic conductance (Gd=1/Rj, where Rj is the juction resistance at Vo)
Then for diode rectifier we have;
----------(3)
then diode current;
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18356-30aceb6f3187c8e2b8c28d3fb5f7bf98.jpg)
Therefore we can say
is the rectified current. Using a low pass filter we can simply get rid of the higher
frequency components
[Microwave Engineering 2nd Ed, David M. Pozar, paged 560-563]
What I cannot understand is these equations are derived from the simple assumption that Input Voltage [equation (3)] is across the diode. But in a
rectifier circuit like this [figure below] will not have Vin across the diode. Then how can I use these equations in this situation?
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18358-f375fc6045ef938bde4c856f9cb222d0.jpg)
I(V) = Is(e^(alpha*V) -1) -----------(1)
Let diode voltage be V=Vo+v --------------(2)
Then, Using taylor series for the diode current I(V) [equation (1)] we have;
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18353-96806ff368fb4eacfda52884d0be008c.jpg)
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18354-e57c728bc7ff4056e987e51a5c80a6c9.jpg)
Then for diode rectifier we have;
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18355-76fbec703ef14e9457d6ac4cd947c7a8.jpg)
then diode current;
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18356-30aceb6f3187c8e2b8c28d3fb5f7bf98.jpg)
Therefore we can say
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18357-6f7d02cbae563b4b52aa5de361bc9897.jpg)
frequency components
[Microwave Engineering 2nd Ed, David M. Pozar, paged 560-563]
What I cannot understand is these equations are derived from the simple assumption that Input Voltage [equation (3)] is across the diode. But in a
rectifier circuit like this [figure below] will not have Vin across the diode. Then how can I use these equations in this situation?
![Capture.PNG Capture.PNG](https://www.edaboard.com/data/attachments/18/18358-f375fc6045ef938bde4c856f9cb222d0.jpg)