# What is the formula for saturation current?

## What is the formula for saturation current?

For silicon diodes a typical saturation current is I S = 1 0 − 12 A \text I_{\text S}=10^{-12}\,\text A IS=10−12A. k is Boltzmann’s constant, T is the temperature in kelvin, and q is the charge on an electron in coulombs.

How is forward bias current calculated?

The forward current approximation, as we will call it, results in the following formula: i(v)≈ISexp(vηVT)v>0.2V.

What is saturation current in forward bias?

The saturation current is a combination of the generation current caused by thermal generation of electron hole pairs within the depletion region of the diode and the diffusion current due to minority carriers in the n and pregions diffusing across the depletion region.

### What are the equation of current I in forward bias and reverse bias?

In a p-n junction diode, the current I can be expressed as I=I0exp(2KBTeV−1), where I0 is called the reverse saturation current, V is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, kB is the Boltzmann constant (8.

What is the forward bias?

Forward bias or biasing is where the external voltage is delivered across the P-N junction diode. In a forward bias setup, the P-side of the diode is attached to the positive terminal and N-side is fixed to the negative side of the battery.

What is the saturation current of a diode?

IS, the reverse bias saturation current for an ideal p–n diode, is given by (Schubert 2006, 61): are the carrier lifetimes of holes and electrons, respectively. Increase in reverse bias does not allow the majority charge carriers to diffuse across the junction.

## How do you calculate saturation current in BJT?

Lets ASSUME instead that the BJT is in saturation. Thus, we ENFORCE the conditions: VCE = 0.2 V VBE = 0.7 V VCB = -0.5 V Now lets ANALYZE the circuit ! + 0.2 – + 0.7 – + -0.5 – iB iE iC Note that we cannot directly determine the currents, as we do not know the base voltage, emitter voltage, or collector voltage.

What is ETA in diode current equation?

η, the (exponential) Ideality Factor. Ideality factor (η) indicates the nearness with which the considered diode behaves with respect to the ideal diode. That is, if the diode under consideration behaves exactly as that of an ideal diode, then η will be 1.

When a pn junction is forward biased the flow of current?

The correct option is C the diffusion of electronsExplanation:When PN junction diode is in forward biased condition then the flow of current is mainly due to diffusion of electrons.

### What is N in diode current equation?

n is the ideality factor, also known as the quality factor or sometimes emission coefficient. The equation is called the Shockley ideal diode equation when n, the ideality factor, is set equal to 1.

What is BJT saturation current?

In a nutshell, “saturation” for a BJT is the point where a further increase in base current will not result in a corresponding increase in collector current.

When pn junction diode is forward bias the current in junction?

If a suitable positive voltage (forward bias) is applied between the two ends of the PN junction, it can supply free electrons and holes with the extra energy they require to cross the junction as the width of the depletion layer around the PN junction is decreased.

## Why does current flow in forward bias?

In forward biased condition, the width of the depletion region is very narrow. Hence, the free electrons and holes easily overcome the weak opposite electric field from the depletion region and cross the depletion region. Therefore, the electric current flows in the forward biased condition.