How To Specify Custom Heater Resistors

Heater resistors are used in a wide variety of applications from simple demisting elements in car windscreens to complex medical applications where demand is increasing for custom heater resistors to satisfy the requirements of demanding and diverse medical applications. In this post we discuss the information required by a specialist resistor manufacturer to design and deliver a application specific heater resistor.

 

When specifying a application specific resistor the key tradeoff is often size versus power rating. This is particularly important in many medical applications where space may be limited. Often heat must be delivered to a specific point contact, in a controlled manner for a specific period of time.

The power rating of a resistor defines the maximum energy (heat) a resistor can safely dissipate with compromising its in service life. In general terms the greater a resistors surface area the more power it can dissipate. Resistor dimensions are also influenced by the choice of substrate material.

Information required by the manufacturer of custom heater resistors includes (as a minimum)

  • Maximum thickness

  • Size (dimensions)

  • Termination type, position and material

  • Heat profile required

  • Contact area

  • Response time

  • Ambient air temperature of environment

  • Voltage

  • Expected in service life

Thick film is an excellent technology choice for custom heater resistor designs. The technology has excellent heat transfer properties, thermal efficiency and temperature uniformity across a surface. Substrates may be custom designed to fit in small, difficult to access, areas and apply heat exactly where it is required. The technology is also robust with excellent  moisture and chemical resistance.

With the application parameters identified it is important to work with a specialist manufacturer who understands resistor technology, materials and design and manufacturing limitations to ensure custom heater resistors are delivered that perform reliably to specification over their full in service life.