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'why can't we determine barrier potential by using a voltmeter connected across the ends of a diode'?
Wiki User
∙ 16y ago
The barrier potential is not a voltage created inside the diode. instead, it refers to the depleted zone around the juncture.
Since this region is deplete from carriers (electrons or holes), it became a virtual isolator. In order to make the depleted zone conductive, you need to apply an external voltage to the diode terminals.
If the voltage is in forward bias (+ to the anode and - to the cathode), you will need 0.2/0.3 V for germanium diodes and 0.6/07 V for silicon diodes. You need an external diode to keep the forward current with safe limits.
If the voltage is in reverse mode (- to the anode and + to the cathode), you will need to apply much more voltage to achieve conduction, although this could permanently damage the diode. Zenner diodes, for instance, always work in reverse bias to create a stable voltage, which is used for regulation purposes.
Wiki User
∙ 16y ago
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Which is greater the breakdown voltage or the barrier potential?
Breakdown voltage is far greater than barrier potential. silicon:- break-down voltage :- 5v - 450 v barrier potential ;- 0.5v to 0.7 V
When a voltmeter is place across a forward biased diode it will read a voltage?
(A) The bias battery voltage (B) 0V (C) the diode barrier potentiaol (D) The total circuit voltage
How is a potential barrier formed?
when a p-n junction is formed electrons from the neutral N type goes to neutral P type. In the junction there will not be any electron or hole. In the junction because of earning electrons, P side becomes negative(ion) , & N side becomes positive(ion). So there will be a potential deference . This is known as the BARRIER......
What is potential barrier in PN junction?
Whenever two dissimilar conductors touch a "potential barrier" forms. All conductive materials have a voltage above zero that an electron must have to enter the material. In true conductors, this voltage is very low. In semiconductors, it can vary, but is usually in the 0.25 to 6.8 Volt range. In insulators, it can be very, very high. When two semiconductors or a metal and a semiconductor touch the difference is polarity sensitive. The higher the "band gap", the voltage that must be overcome to enter the "conduction band", the higher the voltage drop in the forward bias direction. Think of the "band gap", or potential barrier, as being like a curb on a road and sidewalk. It's easy to ride a bike off the sidewalk over the curb onto the road, but not so easy the other way.
Can the barrier voltage of a diode act as a voltage source?
No, we don not consider the barrier voltage of a diode to be able to act as a voltage source. The barrier voltage arises during construction of the p-n junction, and it results from charge separation. Separating charges results in voltage, but this difference of potential cannot be tapped as a voltage source because it cannot supply current the way we understand conventional voltage sources are able do.
Why potential across pn junction is called potential barrier?
The potential across a pn junction is called potential barrier because majority charge carriers have to overcome this potential before crossing the junction.
Which is greater the breakdown voltage or the barrier potential?
Breakdown voltage is far greater than barrier potential. silicon:- break-down voltage :- 5v - 450 v barrier potential ;- 0.5v to 0.7 V
Why can't the potential barrier of a diode be used as a voltage source?
The potential barrier of a diode is caused by the movement of electrons to create holes. The electrons and holes create a potential barrier, but as this voltage will not supply current, it cannot be used as a voltage source.
Compare the characteristics of a silicon and germanium diode?
Potential barrier of silicon is 0.7, whereas potential barrier of germanium is 0.3
What is the potential barrier of germanium?
0.3 volt
What happens to the barrier potential when the temperature increases?
barrier potential P0=(kT/q)*ln(Na*Nd/Ni^2) when T ↑, P0↑.
What happen to barrier potential when temperature increases?
barrier potential P0=(kT/q)*ln(Na*Nd/Ni^2) when T ↑, P0↑.
What is the definition of the word barrier spit?
It is almost like a barrier island just connected to the main land!
Is barrier potential temperature dependent?
Yes, it varies inversely, i.e. as temperature increases the barrier potential decreases. It decreases by 2mV for degree Celsius rise of temperature.
What are forward and reverse bias?
Forward bias is when the height of the depletion layer is reduced such that a greater number of majority charge carriers have sufficient energy to overcome the potential barrier while revers bias is when the height of the potential barrier is increased so that very few majority charge carriers have sufficient energy to surmount the potential barrier. All the above phenomena takes place when a potential barrier is applied across the pn junction.
What is potential barrier factor?
Potential barrier is the energy inserted in order to go against the passage of electron.
Can a lumbar puncture determine the effectiveness of a blood brain barrier?
true
