PN JUNCTION SEMICONDUCTOR DIODE
Forward Bias
It is the condition when the anode is more positive than the cathode.
Breakdown Voltage
It is the maximum voltage that can be handled by the junction diode.
Average AC resistance
It is the resistance associated with the device when a large signal is used as an input to produce a broad swing.
DC or Static Resistance
It is the resistance of the diode at the quiescent operating point.
No electrical current
No electrons move through the PN junction at equilibrium; and since the flow of electrons is electrical current, there is ______________ through the PN junction.
Quiescent
means "still" or "unvarying"
AC or Dynamic Resistance
An application of a varying input (an ac voltage, for instance) will move the instantaneous operating point up and down a particular region since the value of ID and VD will also vary.
Dynamic Resistance
Because the resistance changes as you move along the V-I curve
Reverse Bias
Depletion region wider, no voltage and current
Operating Voltage (Reverse-Bias condition) Type of semiconductor material Cross-sectional area of the junction
Diode capacitance depends on the ff:
Type of semiconductive material Amount of doping Temperature
Factors that barrier potential is dependenr
0.3 @ 25 C
Germanium
100 C
Germanium
drastically increase.
If the external reverse-bias is increased to a value called the breakdown voltage, the reverse current will _________.
higher the current
In DC or Static Resistance, the _________ through a diode, the lower is the dc resistance level.
Forward and reverse
In relation to a PN junction, two bias conditions
Very high reverse current
In reverse breakdown, results in a _______ that can damage the PN structure because of excessive heat dissipation.
Junction Diode
It is a two-terminal electric component that conducts electric current in only one direction, functioning as a one-way valve.
Breakdown Voltage
It is also known as the peak reverse voltage or peak inverse voltage.
Barrier potential
It is also the amount of energy required to move the free electrons through the electric field.
PN Junction
It is formed at the boundary between the two regions.
PN Junction
It is formed when an n-type and a p-type materials are brought together.
Reverse Bias
It is the condition when the anode is more negative than the cathode.
400V
PIV (Ge)
1000 V
PIV (Si)
0.7 @ 0 C
Silicon
200 C
Silicon
DC or Static Resistance
The application of a dc voltage to a circuit containing a semiconductor diode will result in an operating point on the characteristic curve that will not change with time.
Simplified Diode Model
The diode when forward-biased has some threshold voltage and has no resistance.
Piecewise Linear Diode Model
The diode when forward-biased has some threshold voltage and resistance.
Reverse Bias
The positive terminal of the battery applied to the n- type material attracts the free electrons away from the junction.
Forward Bias
The positive terminal of the battery repels the holes on the p-type side and pushes them toward the junction. The negative terminal of the battery repels the electrons and pushes them toward the junction.
small leakage current or reverse current.
The reverse bias voltage forces the minority carriers to drift across the junction and cause a ____________.
Ideal Diode Model
approximates the actual behavior of a practical semiconductor diode by representing it as a simple switch.
Diffusion or Storage Capacitance (CD)
capacitance considered in the forward- bias region
Transition-Region or Depletion-Region Capacitance (CT)
capacitance considered in the reverse-bias region
Diode Equivalent Models
combination of circuit elements that best represents the actual characteristics of a semiconductor diode under a specific operating condition
Transition-Region or Depletion-Region Capacitance (CT)
due to the capacitance created by the presence of opposite charges insulated by the depletion region which acts as insulator.
Diffusion or Storage Capacitance (CD)
due to the charges injected into the regions just outside the depletion region.
Junction Diode
formed by doping one half of intrinsic Si or Ge with a p-type dopant and the other half with an n-type dopant.
Barrier potential
is the potential difference of the electric field across the depletion region.
avalanche
multiplication of conduction electrons
Depletion
refers to the fact that the region near the PN junction is depleted of charge carriers (both electrons and holes) due to diffusion across the junction. None of which can carry current.
Bias
refers to the use of a dc voltage to establish certain operating conditions for an electronic device.
Forward Bias
removes depletion region
Reverse Bias
small current will flow because of the minority carriers
Knee Voltage
voltage wherein the sudden increase in current starts
