Negative temperature coefficient thermistor detection oled module

1), measure the nominal resistance value Rt
NTC thermistor with a multimeter measuring methods and measuring the same way as ordinary fixed resistor that, according to the NTC thermistor nominal resistance choosing the right power block can be directly measured actual value of Rt. But NTC thermistors are temperature sensitive, so the test should note the following: ARt is the manufacturer at an ambient temperature of 25 ℃ measured, so measured with a multimeter Rt, we should at ambient temperature close to 25 ℃, carried out in order to ensure the credibility of the test. B measured power must not exceed the specified value, in order to avoid measurement errors caused by thermal effect of current. C Note correct operation. Test, do not hold hands thermistor body, in order to prevent an impact on the test body temperature.
(2), estimate the temperature coefficient αt 20x2 lcd
T1 first measured at room temperature resistance value Rt1, and then electric iron as a heat source, close to the thermistor Rt, the measured resistance value RT2, while the time measured with a thermometer thermistor RT average surface temperature t2 then calculated.
7 varistor testing. With a multimeter R × 1k block measuring varistor between two pins, the reverse insulation resistance, are infinite, otherwise, indicating leakage current. If the measured resistance is very small, indicating varistor is corrupt and can not be used. 40x2 lcd
8 photosensitive resistance testing. A piece of paper with a black translucent window will photoresistor cover, this time remained multimeter pointer does not move, the resistance approaches infinity. This value is the greater photoresistor better the performance. If this value is very small or close to zero, indicating that the photoresistor has burn damage, can not continue to be used. B will be a light at photoresistor light window, with the multimeter pointer should be more substantial swing, resistance was significantly reduced. This value is smaller the photoresistor better the performance. If this value is large or even infinite, indicate photoresistor open internal damage, can no longer continue to use. C will be aligned with the incident light transmitting window photoresistor lines, with black paper in the upper window shading photoresistor shaking so intermittent light, this time with the black paper multimeter pointer should be shaking and swinging around. If the meter pointer is not always in a position to stop shaking and swinging with the paper, indicating photoresistor photosensitive material has been damaged.