- #1
Garoll
- 8
- 0
Hello,
Here is my question:
If we have a regular PN junction diode, which is forward biased we will observe the effect "injection", we will have more minority carriers than normal near the PN junction. I would like to ask you whether this "injection" is observed during the whole period when the diode is forward biased or it is observed just at the moment of forward biasing the diode.
I am asking this question, because i have got an issue with the frequency characteristics of the diode.
In my textbook it is said:
"When the frequency is low the minority carriers in the base are able to recombinate fully before changing the polarity of the voltage and there is current only in the positive semi-period of the signal.
When we make the frequency higher the rectifying properties of the diode are getting worse. The minority carriers are not able to fully recombinate before changing the polarity and we are observing current in negative semi-period, which is bad."
This explanation leads me to the fact that we observe "injection" only in the moment when we forward bias the diode, but not at the whole time when the diode is forward biased.
Could i ask anyone to clear out these issues, it will be of big help for me.
Regards
Here is my question:
If we have a regular PN junction diode, which is forward biased we will observe the effect "injection", we will have more minority carriers than normal near the PN junction. I would like to ask you whether this "injection" is observed during the whole period when the diode is forward biased or it is observed just at the moment of forward biasing the diode.
I am asking this question, because i have got an issue with the frequency characteristics of the diode.
In my textbook it is said:
"When the frequency is low the minority carriers in the base are able to recombinate fully before changing the polarity of the voltage and there is current only in the positive semi-period of the signal.
When we make the frequency higher the rectifying properties of the diode are getting worse. The minority carriers are not able to fully recombinate before changing the polarity and we are observing current in negative semi-period, which is bad."
This explanation leads me to the fact that we observe "injection" only in the moment when we forward bias the diode, but not at the whole time when the diode is forward biased.
Could i ask anyone to clear out these issues, it will be of big help for me.
Regards