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Photodiode and phototransistor

diode 1n60

To photo diode é uma junção PN ou estrutura PIN que quando uma luz relativamente forte atinge a junção, it excites an electron thereby creating a free electron positively charged. This mechanism is also known as ” photoelectric effect “, also common in transistors and integrated circuits, since they are made of semiconductors, and pn junctions contain.

Almost all active components are potentially photo-sensors. The PN junction needs to be exposed to light, so that for using a semiconductor, como um foto-sensor sua placa de silício deverá ser exposta, in a transparent glass ampoule or pour silicone.

Test circuit light sensor diodes


These diodes with these characteristics can be used to measure the light intensity, above circuit.

photo Transistor

The photo Transistor é essencialmente, a bipolar transistor, que funciona como um fotodiodo, but with a much higher sensitivity to light, since the electrons that are generated by photons in the base-collector junction is applied within the base, its current is then amplified by the transistor operation. However, the photodiode has faster response time than the phototransistor.

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