What are the components of photo detectors?
Grouped by mechanism, photodetectors include the following devices:
- Photoemission or photoelectric.
- Semiconductor.
- Photovoltaic.
- Thermal.
- Photochemical.
- Polarization.
- Graphene/silicon photodetectors.
What is photodiode with diagram?
A photodiode is a PN-junction diode that consumes light energy to produce an electric current. They are also called a photo-detector, a light detector, and a photo-sensor. Photodiodes are designed to work in reverse bias condition. Typical photodiode materials are Silicon, Germanium and Indium gallium arsenide.
What is photo detector principle?
In a photodetector, the incident light is converted into voltage or current. Examples of photodetectors are photodiodes and phototransistors. Working principle of photodetectors is similar to that of the solar cells, in which the incident solar energy is converted into electrical energy.
What are the different types of photo detectors?
Common Types of Photodetectors
- p-n Photodiodes.
- p-i-n Photodiodes.
- Avalanche Photodiodes.
- MSM Photodetectors.
What are the requirements of a photo detector give different types of photo detectors?
Important Properties of Photodetectors. Depending on the application, a photodetector has to fulfill various requirements: It must be sensitive in a certain spectral region (range of optical wavelengths). In some cases, the responsivity should be constant or at least well defined within some wavelength range.
What is photodiode explain briefly its working with the help of circuit diagram?
A photodiode is an electrical device used to detect and convert light into an energy signal through the use of a photo detector. It is a pn-junction whose function is controlled by the light allowed to fall on it. Suppose, the wavelength is such that the energy of a photon, hc/λ, is sufficient to break a valance bond.
What is the difference between photodiode and solar cell?
A photo diode is made to detect light quickly whereas a solar cell is made to collect energy from light. They are both typically silicon diodes, but modified to meet their different requirements. A photo diode has to be fast, which means low capacitance, which means small area of silicon.
What is a basic phototransistor detector circuit?
Visible Light Photo-Detector Circuits Basic Phototransistor Detector. In this circuit, when the light falling on the phototransistor (Q1) is blocked, its conductance will decrease and the voltage across Q1 will rise. When the voltage rises above 1/2 of the supply voltage the output of the comparator will turn ON and the LED will be lit.
How does a visible light photo-detector work?
This page features basic, visible light photo-detector circuits that can be used to detect trains or other light blocking objects. The sensors used for these circuits are silicon phototransistors or Cadmium Sulfide (CdS) photocells. Both of these sensors allow less current to flow when they are dark.
What is photodetector photocurrent?
The photocurrent induced in a photodetector circuit comprises a superposition of current pulses, each associated with a detected photon. The individual pulses illustrated are exponentially decaying step functions but they can assume an arbitrary shape.
What is the voltage of the phototransistor?
The supply voltage for the circuits is specified as regulated 12 volts DC but this can be changed if needed. In some cases the values of some resistors may have to be adjusted to compensate. In this circuit, when the light falling on the phototransistor (Q1) is blocked, its conductance will decrease and the voltage across Q1 will rise.