A photodiode is used to detect and convert light into an energy signal.
A photodiode is an electrical device used to detect and convert light into an energy signal through the use of a photodetector. The photodiode can use a fiber optic element to send light into the diode circuit and convert it into power. It can also perform the same function through a device similar to a solar panel or a window.
In most cases, the photodiode is used to send a trigger signal to an electrical device when it is exposed to UV or X-rays. It can also be used to provide the same trigger signal when the light source is off or on. the photodiode is blocked from the light source. Another function a photodiode can perform is to keep an electrical device running during the process of converting light into an energy or voltage signal.
A photodiode works mainly in a PIN or PN connection structure. This means that the moment a light source such as UV or X-ray can hit the diode, the reaction inside the diode is the interaction of electrons. This interaction between the electrons creates a positively charged hole, which naturally moves towards the anodic connection of the circuit. At the same time, excited electrons are naturally attracted to the cathode connection.
These two natural reactions to the light source create what is known as a photocurrent. This means that the light source has been converted to power, which usually results in the light source being converted to voltage. This converted energy is then delivered to the input signal circuitry of the electrical device it is designed to connect to. This allows the photodiode input signal to power the electrical device through the energy produced in the light source.
There are different uses for photodiodes depending on what they are used for. In photovoltaic mode, for example, the signal generated by the diode exposed to a light source is collected and stored. It is then spread out as an output signal as needed by the device(s) it is connected to.
This mode of use is generally relevant for solar panels. Another mode of use is called photoconductive. In this mode, the energy created by exposing the diode to a light source is used as a direct power signal to the electrical device that is used to power the diode.