IDIOMA (LANGUAGE) : ESPAÑOL
WHAT IS A PHOTODIODE?
It is a PN junction semiconductor, it has sensitivity to the presence of visible and infrared light. It could be considered that a photodiode is the combination of a common diode and a photoresistor or LDR and in the same way that the common diode has its polarization. It should be noted that this electronic component is much more linear than a photoresistor or LDR.
HOW DOES A PHOTODIODE WORK?
For correct operation, the photodiode is reverse polarized, thus allowing the electron’s flow or the current’s flow in the opposite direction. These components have a lens that allows concentrating the light that hits on them, therefore, when the incident light is of sufficient energy it can excite an electron generating movement and allowing the creation of positively charged voids. Therefore, the greater the intensity of incident light on the photodiode, the greater the current that flows.
DIFFERENCE BETWEEN LDR OR PHOTORRESISTANCE, PHOTOTRANSISTOR AND PHOTODIODE
The response time is the biggest difference that we can find between the photodiode and the LDR or photoresistor, being the response time of the photodiode much faster than the LDR. The phototransistor is actually a combination of a photodiode and a bipolar transistor.
TYPES OF PHOTODIODE
In this case there are two types of photodiodes that correspond to the PIN photodiode and the avalanche photodiode. To see more about the family sensors that generate an electrical signal depending on the light or other electromagnetic radiation they receive, we recommend visiting the link photodetector.
Below, we present a brief description of the types of photodiodes. To know more about each one, we provide an underlined link that will allow you to go to another page and learn more about these electronic devices.
- PIN PHOTODIODE: it is an intrinsic semiconductor material of the most common since it allows the intrinsic layer to be modified to optimize the quantum efficiency and the frequency margin.
- AVALANCHE PHOTODIODE: it has a structure very similar to the common photodiode, the advantage is that it allows working with higher inverse voltages. It is normally used when the received power may be limited since its responsiveness is greater than the photodiodes. Its use is not recommended in which signals are used since they introduce noise to the circuit.
NOTE: The temperature is one of the important factors to consider in the electronic components and in this case for the different types of photodetectors, since the gain depends on the temperature. To solve this problem, it is advisable to use a PID control (Proportional Integral Derivative controller) for temperature.