The thermistors offer unique performance capabilities, serving not only as measuring components for temperature, flow, and liquid level, but also as control components like thermal switches and current limiters, as well as circuit compensation elements. Their applications span diverse fields such as household appliances, electric power, communications, military, and aerospace, promising extensive growth opportunities.

 

During thermistor testing, begin by measuring its resistance in a controlled indoor environment. Subsequently, holding the thermistor with your hand allows you to detect any decrease in resistance, indicating normal functionality. Any deviation from this pattern suggests an anomaly. It's crucial to utilize specialized instruments for precise measurements during testing. Below, UF capacitors in China introduces various measurement techniques for accurate assessment.

 

 

1. Room temperature detection of NTC thermistor

 

Set the multimeter to the resistance file, and the two meters touch the two pins of the thermistor. The reading of the multimeter is the resistance value of the thermistor under test at room temperature. On the premise of correct selection of the resistance file, if the reading is o or infinity, it means that the thermistor has been damaged.

 

2. High-temperature detection of NTC thermistor

 

Use an electric soldering iron as a heat source close to the thermistor. If the resistance displayed by the multimeter changes significantly from the resistance at room temperature, remove the soldering iron and the negative value will return to the negative value at room temperature, indicating that the thermistor is good.

 

3. Low-temperature detection of NTC thermistor

 

Clamp the two pins of the thermistor with a multimeter clamp, and put the thermistor into the refrigerator. Normally, the negative value displayed by the thermistor with a negative temperature coefficient is significantly larger than the negative value at room temperature; for the thermal resistance with a positive temperature coefficient, the resistance value displayed by the multimeter is significantly lower than the negative value at room temperature.

 

4. Heating method of NTC thermistor

 

Connect the two lead wires of the thermistor with the resistance gear of a multimeter, and then use a hot electric soldering iron (20W is fine) to heat the thermistor (close to the thermistor). For the PTC type thermistor, as the temperature increases, the resistance value should increase; for the NTC type thermistor, as the temperature increases, the resistance value should decrease. If the thermistor is heated, its resistance does not change, indicating that the thermistor is damaged.

 

5. Multimeter measurement method of NTC thermistor

 

Positive temperature coefficient thermistor (PTC) detection

When testing, the multimeter is adjusted to R×1 gear, which can be divided into two steps:

 

(1) Normal temperature detection (indoor temperature is close to 25℃): The actual resistance value of the two pins of the PTC thermistor is measured by touching the two test leads to the two pins of the PTC thermistor, and compared with the nominal resistance value. The difference between the two is within ±2Ω. normal. If the actual resistance value differs too much from the nominal resistance value, it means that its performance is poor or damaged.

 

(2) Heating test: On the basis of the normal temperature test, the second step of the test—heating test can be carried out. Put a heat source (such as electric soldering iron) close to the PTC thermistor to heat it, and monitor its resistance with a multimeter. Whether the value increases with the increase in temperature, if it is, it means that the thermistor is normal. If there is no change in the resistance value, it means that its performance has deteriorated and cannot be used continuously. Be careful not to put the heat source too close to the PTC thermistor or directly touch the thermistor to prevent it from being burned.

 

Negative temperature coefficient thermistor (NTC) detection

 

(1) Measuring the nominal resistance value Rt: The method of measuring NTC thermistor with a multimeter is the same as the method of measuring ordinary fixed resistance, that is, according to the nominal resistance of the NTC thermistor, selecting the appropriate electrical barrier can directly measure the Rt Actual value. But because NTC thermistor is very sensitive to temperature, the following points should be paid attention to when testing: ARt is measured by the manufacturer when the ambient temperature is 25℃, so when measuring Rt with a multimeter, the ambient temperature should be close to 25 It is carried out at ℃ to ensure the reliability of the test. B. The measured power must not exceed the specified value to avoid measurement errors caused by current heating effects. C pays attention to correct operation. During the test, do not pinch the thermistor body with your hands to prevent the body temperature from affecting the test.

 

2. Estimate the temperature coefficient αt: the first measure the resistance value Rt1 at room temperature t1, and then use an electric soldering iron as a heat source, close to the thermistor Rt, measure the resistance value RT2, and use a thermometer to measure the thermistor RT at this time The average surface temperature t2 is then calculated.
   
   UF Capacitors, is an ISO9001 manufacturer in China founded in 1995, Specializing in NTC Thermistor ( both black and green type). our marketing position is to replace first-tier brands like TDK/EPCOS, thinking etc with similar quality but much better price, faster lead time and excellent service. We have rich experience working with big international companies like GE & Philips, Jabil, Flex etc. 
    

Photo	Description	UF Capacitors Series Code	TDK/EPCOS	Thinking-TVR
	MF72 Power NTC Thermistor	NTC Series	B57 Series B57153S Series	SCK*** Series

 

UF’s NTC Thermistor has following Features

• Small size , Strong power and strong capability of surge current protection.
• Fast response to surge current.
• Big material constant(B value), Small remain resistance.
• Longevity of service, High reliability.
• Integral series , Extensive operating range
• Silicon Epoxy Coating, Copper Leads
• RoHS Compliant

 

And typical application as following:

• Convension power supply , switch power, kinds of electric heater, energy-saving lamps , electronic ballast etc .
• All kinds of power circuit protection of electronic equipment, filament protection of RT, display, bulb, lighting lamps etc.