Today I am going to post a topic on the Diode Parameters And Diode Applications
Diode Parameters :
1) Bulk Resistance (rB)
It is the sum of the resistance values of the P-and N-type semiconductor materials of which the
diode is made of.
∴ rB = rP + rN
Itually, it is very small. It is given by
rB = (VF −VB)/IF
It is the resistance offered by the diode well above the barrier voltage i.e. when current is large. Obviously, this resistance is offered in the forward direction.
2) Junction Resistance (rj)
Its value for forward-biased junction depends on the magnitude of forward dc current.
rj = 25 mV/IF (mA) – for Ge
= 50 mV/IF (mA) – for Si
Obviously, it is a variable resistance.
3) Dynamic Or Ac Resistance :
rac or rd = rB + rj
For large values of forward current, rj is negligible.
Hence,
rac = rB.
For small values of IF, rB is negligible as compared to rj
. Hence rac = r
4) Forward Voltage Drop
It is given by the relation
forward voltage drop = power dissipated
forward dc current
5. Reverse saturation current (I0).
6. Reverse breakdown voltage (VBR).
7. Reverse dc resistance RR
Applications :
The main applications of semiconductor diodes in modern electronic circuitry are as under :
1. As power or rectifier diodes. They convert ac current into dc current for dc power supplies
of electronic circuits.
2. As signal diodes in communication circuits for modulation and demodulation of small
signals.
3. As Zener diodes in voltage stabilizing circuits.
4. As varactor diodes–for use in voltage-controlled tuning circuits as may be found in radio
and TV receivers. For this purpose, the diode is deliberately made to have a certain range of
junction capacitance. The capacitance of the reverse-biased diode is given by C = K/sqrt ( VR)
where VR is the reverse voltage.
5. In logic circuits used in computers
Comment If You Have Any Doubts Regarding This Topic...
Diode Parameters :
1) Bulk Resistance (rB)
It is the sum of the resistance values of the P-and N-type semiconductor materials of which the
diode is made of.
∴ rB = rP + rN
Itually, it is very small. It is given by
rB = (VF −VB)/IF
It is the resistance offered by the diode well above the barrier voltage i.e. when current is large. Obviously, this resistance is offered in the forward direction.
2) Junction Resistance (rj)
Its value for forward-biased junction depends on the magnitude of forward dc current.
rj = 25 mV/IF (mA) – for Ge
= 50 mV/IF (mA) – for Si
Obviously, it is a variable resistance.
3) Dynamic Or Ac Resistance :
rac or rd = rB + rj
For large values of forward current, rj is negligible.
Hence,
rac = rB.
For small values of IF, rB is negligible as compared to rj
. Hence rac = r
4) Forward Voltage Drop
It is given by the relation
forward voltage drop = power dissipated
forward dc current
5. Reverse saturation current (I0).
6. Reverse breakdown voltage (VBR).
7. Reverse dc resistance RR
Applications :
The main applications of semiconductor diodes in modern electronic circuitry are as under :
1. As power or rectifier diodes. They convert ac current into dc current for dc power supplies
of electronic circuits.
2. As signal diodes in communication circuits for modulation and demodulation of small
signals.
3. As Zener diodes in voltage stabilizing circuits.
4. As varactor diodes–for use in voltage-controlled tuning circuits as may be found in radio
and TV receivers. For this purpose, the diode is deliberately made to have a certain range of
junction capacitance. The capacitance of the reverse-biased diode is given by C = K/sqrt ( VR)
where VR is the reverse voltage.
5. In logic circuits used in computers
Comment If You Have Any Doubts Regarding This Topic...
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