What are PTC heaters? FAQ

What are PTC heaters?

PTC stands for positive temperature coefficient. PTC means that the small ceramic heating element heats quickly but creates an increase in resistance as the temperature increases.  This logarithmic relationship increases the resistance to a point where no current will flow as the heater reaches the maximum temperature.

The most common type of PTC heating element are small ceramic disks doped with quantities of other elements that create unique properties.  Manufacturers have produced the same effect in conductive inks.  

The set-point or maximum temperature is manufactured into the ceramic disk and remains  

constant during the element’s life.  Since the resistance is low when power is applied to the element, it heats quickly but shuts down as the temperature increases to the threshold.  This makes the device self-regulating without the need for external controls.

These properties of PTC heaters allow the circuit to adjust for ambient temperature adding to the self-regulating advantages of the heating element.

Where are PTC heaters used in Industry?

Due to the heating elements’ small size and no requirements for control circuitry, they can be found in a broad range of applications.  PTC heaters are used in industrial panels, sophisticated aerospace, military, medical devices, and lab equipment to more common consumer applications such as hair driers and room heaters are just a few.  

If you have a heated seat or steering wheel in your automobile or truck, the chances are it is a PTC heating element providing the heat.  The devices are found to control the heat in immersion heaters and flexible silicone rubber heaters.

They are also widely used in the farm and construction industries.  In homes and office buildings, PTC heating elements are embedded into fins and honeycomb heat transfer devices for the natural convection or forced air.

Why use a PTC heater?

Safety is one of the primary reasons for using PTC heaters.  The devices have self-regulating properties and no combustible elements to come into contact with flammables without extra insulation.  They also offer high voltage isolation for personal protection.

The heating elements require no maintenance.  PTC heating elements can be easily bonded to heat transfer materials such as silicon and aluminum fins for air and surface heating.  They can operate in temperatures from -40 F to 158 F degrees.

In applications where controlling power consumption is essential, these heaters exceed what traditional resistance heaters can offer since they self-regulate.

The small size of the heaters compared to heat output makes them ideal for use in small medical devices or aerospace applications.  Operating at 6 to 12 Volts AC or DC is also a plus to the miniature applications.

PTC heaters outperform conventional in most applications.  Learn how PTC heaters work and how to use them in your applications.