Photoelectric characteristic experiment of photoresistor

Experiment 24 Photoelectric characteristics of photoresistor

【Purpose requirement】

1. Understand the characteristics of photoconductive photoelectric sensors;

2. Measure the photoelectric characteristics of the photoresistor.

【Experimental Principle】

The photoelectric sensor is a sensor that uses a photoelectric device as a conversion element. It can be used to detect non-electricity that directly causes a change in light quantity, and can also be used to detect other non-electricity that can be converted into a change in light quantity. The photoelectric sensor has the advantages of fast response, reliable performance, and non-contact measurement, so it is widely used in the field of detection and control.

The photoelectric conversion element that works based on the photoelectric effect principle is called a photoelectric device or a photosensitive element. The photoelectric effect is generally divided into external photoelectric effect, photoconductive effect and photovoltaic effect (referred to as photovoltaic effect). The corresponding photoelectric devices also have the following three types: photoelectric emission type, photoconductive type and photovoltaic type.

When most high-resistivity semiconductors are irradiated with light and absorb photon energy, the phenomenon of reduced resistivity and easy conduction occurs. This phenomenon is called the photoconductive effect. There is no electron emission from the inside of the substance, only the resistance inside the substance is changed, so the photoconductive effect belongs to the internal photoelectric effect. Photoresistor is a semiconductor photoelectric device that works based on the principle of photoconductive effect.

【Experiment content】

1. Measure the resistance of the photoresistor with a digital multimeter and observe the characteristics of the photoresistor;

2. Measure the volt-ampere characteristic curve of the photoresistor under the conditions of closed light and visible light;

3. Measure the light characteristics (relative) of the photoresistor.

【Instruments】

Serial number

equipment name

Model / Specification

Unit price (yuan)

Remarks

1

Design experimental device of photoelectric sensor

DH-SJ3

4500

Including photoresistor, DC power supply, small light bulb (6V, 0.15A), experimental dark box, wire, switch

2

DC constant voltage and current source

DH-VC3

900

Compatible with other experiments

3

4 and a half digital multimeter

DY2106

290

The experiment requires two pieces, which can be used in common with other experiments