Thermistor

Semiconductor thermal resistance is the use of thermal properties of semiconductor materials semiconductor resistance work. It is extremely sensitive to temperature changes in the semiconductor material changes its resistance with temperature for very obvious change.

Thermistor is mainly used in temperature measurement, temperature control, temperature compensation, automatic gain, microwave power measurement, fire alarm, infrared detection and regulation, steady rate and so on, is an important element in automatic control equipment.

Thermistor according to their structure is divided into direct thermal and thermal near two major categories.

Direct Thermal thermistor is generally used manganese, magnesium, cobalt, nickel, iron and other metal oxide powder extruded into rods, sheets, washer-like or bead-shaped resistors, after 1000 ° C to 1500 ° C sintered at high temperature, and then fired and silver electrodes, welding wire made of. Heating current directly through the resistors. -35 In the chart shows the thermistor bead-like structure and directly heated thermistor symbols.

Next to the thermal structure of the thermistor and symbols as shown in the chart -36. This thermal resistance posed by the resistors and the heater. Resistors with wire wound next to the heater (heating coil), two tightly coupled together, but each other insulation. And the heater resistors sealed in high vacuum within the pumping into the glass shell, leads to electrodes. Heater through the heating current, the resistance around the body temperature, leading to resistance to change.

According to the different temperature coefficient of resistance, thermal resistance is divided into positive and negative temperature coefficient thermistor temperature coefficient thermistor. Operating temperature range, the positive temperature coefficient thermistor resistance increases rapidly with increasing temperature, negative temperature coefficient of the resistance decreases rapidly with increasing temperature. The latter is widely used. In addition, the thermal resistance as a thermal characteristics of the voltage and current no longer maintain a linear relationship between, as a nonlinear component of the.