What is saturation current in photoelectric current?

The maximum value of the photoelectric current is called the saturation current. Saturation current implies that all the photoelectrons emitted by the emitter are immediately collected by the anode.

What is saturation current?

Definition of saturation current : the limiting current through an ionized gas or an electron tube such that further increase of voltage produces no further increase in current.

How do you find saturation current?

2 Answers

  1. Measure current with fairly large reverse bias, to give you Is. ( for example, -20V for a 1N4148)
  2. Measure forward voltage with fairly large forward current (for example, 20mA for a 1N4148) and calculate the emission coefficient: n=VFVT⋅ln(I/IS)

What does saturation current depend on?

The value of saturation current depends on intensity. It is independent of stopping potential.

What is saturation current and stopping potential?

This maximum value of current is called “Saturation Current”. Now the potential of anode is to be reversed ( – ve ). If this negative potential applied to anode is gradually increased the number of photoelectrons reached to anode decreases and finally becomes Zero.

What is saturation current in pn junction diode?

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.

Is saturation current a constant?

This current is almost independent of the reverse voltage. IS, the reverse bias saturation current for an ideal p–n diode is given by: where Note that the saturation current is not a constant for a given device; it varies with temperature; this variance is the dominant term in the temperature coefficient for a diode.

What is meant by saturation current in PN junction?

Why does saturation current increase with increasing light intensity?

If we increase the intensity of the incident radiation by keeping the frequency constant, then the value of saturation current has increased in propotion to the intensity of the incident radiation, while the stopping potential is still the same. Thus, on increasing the intensity the saturation current also increases.

Does saturation current depend on wavelength?

The saturation current depends on the intensity of light, not on frequency. Hence no matter how much is the frequency for the same intensity of light, the saturation photocurrent will be same.

What is saturation current in BJT?

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.