Positive Temperature Coefficient

What are PTC Heaters?

Positive Temperature Coefficient Heating Elements

How does the PTC heating element work?

PTC heating technology is unique in the family of electrical heating systems.  As current passes through the ceramic element, the resistance to the current produces heat, just as in resistive wire heaters. 

A PTC heating element or positive temperature coefficient heating element is composed of advanced ceramic material or ceramic stones with a small amount of barium titanate.  The doping procedure sets the maximum temperature of the ceramic component and provides the PTC characteristics.

The temperature operating range of the positive temperature coefficient PTC heaters is 40 degrees C to 220 degrees or 104 degrees F - 428 degrees F.  Keep in mind that is the temperature of the actual ceramic heating element.

When the heat rises in the heater, the resistance also increases logarithmically. This fast-rising resistance curve reduces the current going through the heater and the resultant heat.  

The PTC ceramic heating elements are embedded in heat transfer materials that isolate the voltage and current from external contact and efficiently transfer the heat to other materials or air.

PTC air heater, aluminum honeycomb or v patterned structures are set between conductive bars containing the heating element.  These structures are placed in ductwork where the air flows to transfer heat to the air stream.

PTC fan heaters are used for similar purposes in vehicles where a separate fan isn’t practical or available to transfer heat to compartments.

PTC convection heaters are used in electrical enclosures and other applications where there can be natural convection of air passing through the heating elements fin structure.  

PTC surface heaters also have an aluminum fin structure that is attached directly to the surface of the object to be heated. 

PTC immersion heaters or cartridge heaters have the ceramic heater embedded in heat transfer material inside a round or square tube of stainless steel that is inserted into the side of a container with contents to be heated.

Call our team of thermal management specialists.  You will talk with an engineer that is very familiar with all of the devices available and can walk you through finding the proper PTC heating device for your application.

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What are PTC, Positive Temperature Coefficient, Heaters?

What is Positive Temperature Coefficient?

If a material exhibits a positive temperature coefficient means that as its temperature increased its resistance to current raises proportionately.  Initially, the current through these devices will rise sharply with the low resistance but then decrease to zero when the design temperature is reached.  During manufacturing these devices are made to reach a specific temperature.

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PTC Heater Types Explained

PTC ceramic heating elements are used throughout our industrial economy.  Their compact size, efficient heat transfer, reliability, and ability to self-control the amount of heat produced are highly valued.  PTC heating elements are found in our homes, cars, trucks, trains, planes, ships, medical equipment, industry & manufacturing.  

The small PTC ceramic materials or disks, specially made for specific temperatures, are encased in materials that facilitate thermal energy transfer for this compact source.  The small ceramic stones are doped with barium nitrate during manufacturing for specified temperatures.   These set-point temperatures are what make these elements unique in heating applications.

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How to transfer heat from a PTC heating element

PTC element heat transfer   Medical Laboratory Maintains Temperature with PTC Heating Elements   The ceramic heating element designed with PTC, positive temperature coefficient, characteristics require a heat transfer medium to move the heat from the component to the material requiring heat.  The heat transfer design is dependent on the material, distance, and surface area. Heat transfer is heat moving from a warmer object to a cooler thing.  Heat is a measure of the kinetic energy possessed by an item.  The heat measure of an object changes with time until equilibrium between the warmer and cooler things.   Conductive heat...

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How does a PTC heater work?

Traditional resistive element heating

Resistance in a circuit produces thermal energy, which equates to heat.  Nichrome, a non-magnetic alloy of nickel and chromium, is one of the most common resistance wires.  The material has a high resistance to current and oxidation at high temperatures. Other materials and alloys are used for specific applications to create heat with some coated with heat-conducting materials that protect the elements from oxidation at high temperatures. Typical lengths of each type of wire produce the desired heating.  

Forced air or natural convection heat exchangers are utilized to transfer heat to the atmosphere, solids, and liquids.  This heating device has long been used for electrical heating in homes, transportation, and industrial applications.  The resistance is chosen concerning temperature requirements, voltage, and current.  In most applications, temperature sensors and current-limiting components are required to maintain the proper temperature.The current through such wire resistors is nearly constant and does not change with temperature, nor does the wire's resistance.

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