# Is Ohmic Resistance Applicable to Diodes?

• CaptainMarvel1899
In summary, the Drude model is correct for all ohmic resistances and a diode has ohmic resistance even in forward bias.
CaptainMarvel1899
Well I was just wondering how ohmic resistance works in a diode . I mean let's take forward bias mode.In forward bias mode electrons are diffused from the n type region to the p type region.The depletion layer still exists but is very narrow.So according to Drude model of ohmic resistance electrons bump into atoms of the resistor and lose all their momentum during the movement of them opposite of the battery voltage.But in a pn junction diode those atoms are basicly negatively charged because the boron atoms in the depletion layer are negatively charged . So how does this work?

Ohmic Resistance is not universal. It applies in Metals but you can’t expect to find it in all (non-linear) materials.

Im a sure drude model is correct for all ohmic resistances and a diode has ohmic resistance even in forward bias.

CaptainMarvel1899 said:
Im a sure drude model is correct for all ohmic resistances and a diode has ohmic resistance even in forward bias.
If you're sure, then what is the point of this thread?

Dale
The B- ions are negatively charged so I ask if this will affect somehow.

Once the depletion region is closed the diode behaves similar to a conductor. That is why you must put a current limiting resistor in the circuit.

That is why a diode is different than a regular ohmic device. The dopants are charge carriers making the material conductive not resistive.

Drude model also is correct for conductors.The depletion region isn't disappeared it get very narrow.

CaptainMarvel1899 said:
Well I was just wondering how ohmic resistance works in a diode . I mean let's take forward bias mode.In forward bias mode electrons are diffused from the n type region to the p type region.The depletion layer still exists but is very narrow.So according to Drude model of ohmic resistance electrons bump into atoms of the resistor and lose all their momentum during the movement of them opposite of the battery voltage.But in a pn junction diode those atoms are basicly negatively charged because the boron atoms in the depletion layer are negatively charged . So how does this work?

The Drude model predates quantum mechanics and the understanding of how particles behave at the atomic and subatomic scale. What you really want to look at is the free electron model. In this model, there are relatively few ion-electron collisions. The mean free path of an electron is influenced more by lattice defects, impurities, and thermal fluctuations and how these influence the electric potential and band structure of the local area.

When I was a student 60 years ago we were taught the Drude model but let's look at this free electron model.

Nothing is true.Everything is permitted
Evie Frye

osilmag said:
That is why a diode is different than a regular ohmic device. The dopants are charge carriers making the material conductive not resistive.
The term 'Ohmic' refers to a constant ration between PD and Current - in my experience. A diode doesn't behave like that. If you insist, you can measure the PD and the Current for one value of Current and you could assign a value of R (V/I) but that R will not be constant so it doesn't mean much. The R, measured this way will drop rapidly, once the 'knee' voltage of around 0.7V is exceeded.

## 1. What is Ohmic Resistance in diodes?

Ohmic resistance in diodes refers to the resistance that is present in a diode when it is conducting current in the forward direction. This resistance is typically very low and is often ignored in calculations.

## 2. How is Ohmic Resistance calculated in diodes?

Ohmic resistance in diodes can be calculated by dividing the forward voltage drop by the forward current. This will give the value of the resistance in ohms.

## 3. How does Ohmic Resistance affect the performance of diodes?

Ohmic resistance can affect the performance of diodes by causing a voltage drop and reducing the efficiency of the diode. It can also cause the diode to heat up, which can lead to damage if the resistance is too high.

## 4. What factors can affect Ohmic Resistance in diodes?

The main factors that can affect Ohmic Resistance in diodes are temperature, current, and the material used to make the diode. Higher temperatures and higher currents can increase the resistance, while different materials may have different resistance values.

## 5. How can Ohmic Resistance be minimized in diodes?

To minimize Ohmic Resistance in diodes, it is important to choose diodes with low resistance values and to operate them within their specified temperature and current limits. Additionally, using proper heat dissipation techniques can also help reduce the resistance and improve the performance of diodes.

• Electromagnetism
Replies
4
Views
4K
• Electromagnetism
Replies
10
Views
3K
• Electrical Engineering
Replies
8
Views
2K
• Electrical Engineering
Replies
7
Views
2K
• Other Physics Topics
Replies
14
Views
4K
• Introductory Physics Homework Help
Replies
2
Views
1K
• Electrical Engineering
Replies
12
Views
1K
• Electrical Engineering
Replies
5
Views
2K
• Electrical Engineering
Replies
5
Views
2K
• Atomic and Condensed Matter
Replies
8
Views
4K