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PTC Thermistors

PTC is an acronym for "positive temperature coefficient."

The term "PTC" of PTC Thermistor is abbreviation of Positive Temperature Coefficient and is one of resistor with positive temperature characteristics. PTC Thermistor is also one of Ceramic Semiconductor which signifies its characteristics by adding trace amount of rare earth to Brium Titanate(BaTiO₃)which is one of ferroelectric. The above phenomena were discovered by Dr.Haayman and his collegues in 1951 and the subsequent investigations have been done by its researchers. We, Maximum Technology, have been producing highly-pure raw materials by Liqiuid Phase Manufacturing Method different form the method other manufacturers using and successfully developed low resitance PTC Thermistor (1-3Ω・cm)as strong presence in the world.

Our PTC Thermistors have been accepted by many users as suitable automotive parts with compat size.
In addition, our Thermistors have been adpted as Engine parts as big power heater.

We, Maximum Technology, are responding quickly for requirements from various customers with packages of every performances (ie. Size, Resistance value, Curie Temperature, etc.) and the range of TC (Curie Temperature) will be varied between 10℃ and 250℃.

Basic Features of PTC thermistor

1. Using their resistance vs. temperature characteristics

The right figure shows relations between Resistance and Temperature of PTC Thermistor. The resistance value is almost constant from room temperature to Curie temperature and after reaching the Curie Temperature, the resistance value is to be increased quickly.

The constant resistance value at room temperature and Curie temperature are to be varied by material composition of PTC thermistor. According to the above characteristics PTC thermistor is to be used as detector for destroying of semiconductor part by heating problem and for overheating prevent from fire.

2. Using their static characteristics

The right figure shows typical relations between Current(I) and Voltage(V) of PTC Thermistor. The range of constant resistnace value is kept until reaching Curie temperature(Tc) (the maximum point of electrical current value) during electrical current value is increased by voltage rose, then the range of constant electric power is to be come. This feature is to be used for Heater and Part for over current protection.

The PTC thermistor for Heater is self-temperature control type and to be used under the range of the constant electric power(Wattage)not affected by environmental temperature and applied electric voltage. PTC thermistor has no switching noise, which is happened by use of Bi-metal, and is long-life type and is keeping constant temperature without any fluctuation Especially, our PTC thermistor is smaller size and can rise temperature quickly and make high power with low resistance value.

The PTC thermistor for Over current protection is to be used by sudden resistance value increasing just after Cury Temperature reached by over current applied. The thermistor is to be used similar to fuse but with resettable protection as many times as requested. Especially, our PTC thermistor for Over current protection has quick response ability by smaller size with low resistance value.

3. Using their dynamic characteristics

The left figure shows the relations between current and time after putting voltage. Just after Voltage, resistance value is small and current valueis rather big. After sometime passed, resitance value of PTC thermistor is to be increased by their self- heating performance, then Current value become smaller.

The above characteristics are to be used for motor starter and relay-delay circuit, etc..


1. Manufacturing technology for low-resistance materials

Our Liquid -phase method, different from other makers, is providing sintered body with uniform particle size and grain boudary.World class low resistance value is to be provided by the uniform material and is making smaller size thermistor.

Manufacturing Process for PTC Products

Our process flow for PTC Thermistor and its applied products is as follows:

  1. [Liquid-phase method]
    Manufacturing PTC material powder
  2. Press
  3. Sintering
  4. Forming electrodes
  5. Various assembling steps
  6. Inspection and shipment