Photoconductive resistance (hereinafter referred to as CdS) is a special kind of resistance, the abbreviation light resistance, alias optical tube. Its resistance and the strength of the light has a direct relation. The light intensity increases, the resistance decreases, Light intensity decreases, the resistance increases.

When a light ray, resistance within originally in a stable state of electronic is motivated to become free electrons. So the light is stronger, produce of free electrons are also more, the resistance will be small.

Dark resistance: when resistance in completely without radial illuminate condition (room temperature), says when resistance for dark resistance (when resistance stability constant, for example), and dark dump ohms resistor corresponding current as dark current.

Light resistance: when resistance in enough light irradiation condition (room temperature), says when resistance to light resistance (when resistance stability constant, for example one ohm), with bright resistance corresponding current as bright current.

While photo-current = light electricity - dark current

Of course we hope photoconductive resistance of high sensitivity, i.e. photo-current is bigger.

Photosensitive sensor is an photoconductive resistance characteristic of PN junction, has unilateral conductivity, so that the work should add reverse voltage. No light, there is a slight saturated reverse leakage current, namely the dark current sensor, when photosensitive deadline. When exposed to light, saturated reverse leakage current increase greatly, forming photo-current, which over incident light intensity changes. When a light ray PN junction, can make the PN junction produces in the electronic a hole for, make minority carriers increase of density. These carriers in reverse voltage drift, make reverse current increase. So can use light strength to change the current in the circuit.

In addition, photosensitive sensor has instead of photoconductive resistance characteristics, can follow a light changes linear output. And low dark current, low intensity of illumination, have a certain temperature stability. Meet the RoHS requirement.our products (lead-free/no cadmium).

A thermistor is sensitive components category, in accordance with the temperature coefficient of different cent is the temperature coefficient of thermal resistor (PTC) and negative temperature coefficient NTC thermistor (). Thermistor are typically sensitive to temperature, different temperatures showed different resistance. Is the temperature coefficient of thermal resistor (PTC) in the higher the temperature is, the greater the resistance value when negative temperature coefficient NTC thermistor () in the higher the temperature is, the lower the electrical resistance when, they belonged to the semiconductor devices.

PTC (making) refers to Coeff1Cient Temperature in a certain Temperature resistance increased dramatically, has the Positive Temperature coefficient of thermal resistor phenomenon or materials can be specially used for constant Temperature sensor. General ceramic process shaping, high Temperature sintering and make titanate platinum etc., and interstitial semi-conducting water-resistant optimization, thus obtains are characteristics of NTC thermistor materials. The Temperature coefficient and Curie Temperature with components and sintering point conditions (especially cooling Temperature) changed. PTC thermistors except used for heating element outside, also can play the role of "switch", and with the sensitive components, heater and switch three functions, called "heat-sensitive switch". Current through components hind to cause temperature, namely the temperature rises, when more than Curie temperature, resistance increases point, thereby limitting current increasing, then current drop caused force-sensing element temperature drop, the decrease of the current increasing, and the circuit elements temperature, round and round, so as to keep temperature in particular range of function, and then have switch function. Using this resistance temperature characteristics make heating source, as the heating element applications have warm wind instrument, DianLaoTie dryer, wardrobe, air-conditioning, still can rise to the appliance overheating protection function.