# Finding the current in the drain of a MOSFET

• bl965
In summary, to determine the current in the drain of a MOSFET, you can use Ohm's Law by dividing the voltage at the drain by the resistance of the MOSFET. The current is affected by the gate voltage, the drain-source voltage, and the resistance of the MOSFET. It is directly proportional to temperature, but high temperatures can damage the MOSFET. The current can be controlled by adjusting the gate voltage and can be measured using a multimeter in series with the drain of the MOSFET.
bl965

## Homework Statement

The equations provided require the oxide permittivity (εox)as well as the oxide thickness (tox) to determine the gate oxide capacitance per unit squared (Cox). How to solve this?

## Homework Equations

In triode region: ID = μn * Cox * W/L * ((VGS-Vth)* VDS - VDS2/2

In saturation = μn * Cox * 1/2 * W/L * (VGS-Vth)2 * (1 + λ*VDS)

Cox = εox / tox

## The Attempt at a Solution

Without εox, I can't get Cox; I can't start.

tox is given. εox you should be able to look up. Assume the device uses silicon dioxide as the gate dielectric.

## 1. How do you determine the current in the drain of a MOSFET?

To determine the current in the drain of a MOSFET, you can use Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). Therefore, the current can be calculated by dividing the voltage at the drain by the resistance of the MOSFET.

## 2. What factors affect the current in the drain of a MOSFET?

The current in the drain of a MOSFET is affected by the gate voltage, the drain-source voltage, and the resistance of the MOSFET. The gate voltage controls the flow of electrons from the source to the drain, while the drain-source voltage determines the strength of the electric field in the channel. The resistance of the MOSFET determines how much current can flow through the device.

## 3. How does the current in the drain of a MOSFET change with temperature?

The current in the drain of a MOSFET is directly proportional to the temperature. As the temperature increases, the kinetic energy of the electrons in the channel also increases, resulting in a higher current. However, at very high temperatures, the MOSFET may become damaged and its performance may be affected.

## 4. Can the current in the drain of a MOSFET be controlled?

Yes, the current in the drain of a MOSFET can be controlled by adjusting the gate voltage. By changing the gate voltage, the strength of the electric field in the channel can be altered, which affects the amount of current flowing from the source to the drain.

## 5. How can you measure the current in the drain of a MOSFET?

The current in the drain of a MOSFET can be measured using a multimeter. Set the multimeter to measure DC current and connect it in series with the drain of the MOSFET. The multimeter will display the current flowing through the drain of the MOSFET.

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