NTC Thermistor Temperature Sensors

The word “thermistor” comes from the words THERMally sensitive resISTOR. A thermistor is a thermally sensitive semiconductor which gives a change in resistance as the temperature changes.

A Thermistor consists of a resistive element (or bead) and 2 wires. These wires can either be next to each other or opposite (axial). The resistive element is made of semiconductor metal oxides (ceramic materials) or silicon, depending on the application, either of these materials can be used for positive and negative temperature coefficients are used. Electricity passes through the resistive element – as the temperature increases, the resistance decreases, the electricity can flow faster and the thermistor gives a different output, the output is converted into a useable format for the operator. This is how a thermistor measures temperature.

There are two types of thermistors; NTC Thermistors (Negative Temperature Coefficient) and PTC Thermistors (Positive Temperature Coefficient). NTC thermistors have a negative temperature coefficient. This means that NTC Thermistors conduct electricity better at high temperatures than at low temperatures (-3% to -6% change in resistance per 1 ° C increase in temperature). NTC Thermistors can be used to measure temperatures up to 250 ° C and are used to limit inrush currents to allow for a soft start, thus preventing current spikes.

A PTC thermistor is a thermosensitive sensor; the resistance increases significantly with temperature. PTC thermistors are used, among other things, for overload protection and for current limitation in continuous operation. PTC thermistors are often used in motor applications as a way of protecting from over-heating as this could lead to a reduction in power or engine shutdown. Versions with ceramic materials can be used up to about 250 ° C.

Thermistors are relatively cheap and provide a fast response so they are well suited for use in home appliances such as; kettles, coffee machines, boilers, washing machines and microwaves. They are also used in bigger more industrial applications such as;

• Environmental monitoring
• Aerospace applications
• Industrial process
• Healthcare and patient monitoring
• Medical applications
• Communications and computing equipment

As well as being low cost and easy to use, NTC thermistors have the following advantages;

• Highly sensitive
• Ability to work accurately over a small temperature range
• Small in size for tight spaces
• Cheap to replace
• Fast response
• Customisation options
• Compatible with many devices

All of our NTC Thermistors can be seen above. Choose from the different resistance values to see more options including glass or epoxy beads.

• 1k thermistors
• 3k thermistors
• 5k thermistors
• 10k thermistors
• 30k thermistors
• 50k thermistors
• 100k thermistors

NTC Thermistors are a small part of our temperature range of products. To see all of our temperature products please visit the temperature page of our website.

For more information on NTC Thermistors or on any of our products please contact us.