1004,West-CBD,No.139 Binhe Rd,Futian District,Shenzhen, China Post Code:518048

+86-18682200597

sales@szhaiwang.com

  • About Us
    Company Profile Enterprise Honor Factory Environment Company Culture Development Path
  • Product
    Microwave Sensor Series PIR Sensor Series LDR Sensor and Light Sensor Thermistor Sensor Series Fresnel Lens Reminder Alarm Sensor
  • News
    Company News Industry News Latest News
  • Service
    FAQ Download
  • Contacts

    Home  -  News  -  Industry News

    Resistance tolerance of NTC and corresponding temperature tolerance.SMD PIR IC Manufacturing

    source:Industry News release time:2022-06-25 Hits:     Popular:Infrared sensing module


      

      The resistance tolerance of NTC is different at different temperatures, as shown in the following formula, the resistance tolerance at different temperatures is affected by the resistance R25 tolerance and B value tolerance at room temperature

      When NTC is used for temperature detection, usually we need to know the temperature tolerance that NTC can support, so we need to convert, divide resistance tolerance by ɑ temperature coefficient,

      The R-T table of NTC is the information that electronic engineers must obtain when designing circuits. The table is calculated by formulas, so the temperature interval can be set freely. In view of the accuracy of NTC temperature detection, the temperature interval is usually set to 1°C .

      After an in-depth understanding of the basic parameters of NTC, let's take a brief look at how to use NTC in a circuit.

      When NTC is used for temperature detection, monitoring or compensation, it is usually necessary to connect a resistor in series. The choice of resistance value can be determined according to the temperature area that needs to be detected and the amount of current flowing. Generally, a resistor at room temperature is connected in series with the NTC. Resistors with the same value, and ensure that the flowing current is small enough to avoid self-heating and affect the detection accuracy. The detected signal is the divided voltage on the NTC resistor. If you want to get a more linear curve between the voltage and the temperature, you can use the following circuit

      The matters needing attention in the use of NTC are as follows

      1. Be sure to add a suitable series resistance, otherwise thermal collapse will occur when the NTC is in use, because the current flowing through the NTC will generate heat. If the heat cannot be dissipated in time, the temperature of the NTC will increase, and then the resistance value will decrease. At this time, the current will increase. Significantly increased, the NTC will become hotter, and such cycling may eventually cause the NTC to burn out, or even catch fire.

      2. The end electrodes of NTCs are usually composed of Ag, which migrates when improperly used, causing the NTC to short-circuit. Avoid contact of NTC with water during use.

      3. High temperature during soldering will cause irreversible resistance drift of NTC, which may cause 5% drift in some cases, so try to avoid high temperature soldering.

      4. NTC SMDs are constructed of ceramic and may break during installation


    Read recommendations:

    NTC thermistor and inrush current

    Comparison of typical applications of circuit protection devices such as NTC, PTC, TVS, MOV, etc.ala

    PIR Lens 7707-15

    SMD CDS Sensor

    HW1004PIR sensor module

    Popular Recommended Products