NTC thermistor nonlinear correction method

The thermistor has the characteristics of high sensitivity, good stability, fast response, long life and low cost. The NTC thermistor can be widely used in temperature measurement, temperature compensation, and suppression of surge current.

The commonly used NTC thermistor nonlinear correction method uses a fixed resistor with a small temperature coefficient in parallel with the thermistor. This method is simple and easy to use and has a good correction effect. It has a cold junction of the NTC thermistor curve. Pull down the effect.

For example, when two resistors are connected in parallel, the lower resistance value has a greater effect. The resistance value of the cold junction thermistor is higher, the parallel fixed resistor plays a major role, and the thermistor itself has a steeper resistance value change (large temperature coefficient). Because of the action of the fixed resistor; while the hot end, the thermistor has a lower resistance value relative to the fixed resistor, so the resistance value of the thermistor changes significantly.

The thermistor has a temperature measurement range of -100°C to 500°C and a sensitivity of -44000ppm/°C (at 25°C). Its practical size is very flexible and can be as small as 0.01 inch or less. Limited scope. The rated room temperature resistance depends on its semiconductor material, size, shape, and contact area of the electrode. Thick and narrow thermistors have relatively high resistance values, while thin and wide shapes have lower resistance values.

Good linearity is usually required when used as a temperature sensor. However, the resistance value of the thermistor changes exponentially with temperature. In a large temperature range, the relationship between resistance and temperature has a relatively serious nonlinearity. At this time, a nonlinear correction will achieve better results.