NTC vs. PTC Heating Elements
I made the mistake of asking my husband “Sparky” the difference between NTC and PTC heating elements. His description that follows was actually interesting. It does amaze me that engineers developed such products to meet such a variety of temperature control applications.
What's the Difference Between NTC and PTC?
Across a range of industries, Positive Temperature Coefficient (PTC) heaters offer myriad benefits, including a simple troubleshooting approach, minimal maintenance, and secure, efficient heat transfer.
Despite their apparent advantages, they're still competing with their counterparts, Negative Temperature Coefficient (NTC) heaters. With multiple options on the market, engineers and program managers might find it challenging to select the specific heating elements suitable for their project.
Unsure which model is the best fit? Read on to learn more about PTC vs. NTC heaters, and why PTC solutions are ideal for most industrial heating scenarios.
Understanding PTC Heaters
Does your industrial project require safe, quick and uniform heating? If so, PTC heaters are preferable over any other type. These self-regulating heaters run open-loop, without the need for external diagnostic controls.
Engineers in the industry have likely worked with traditional, fixed-resistance heaters for years. These generate heat through the employment of wires and coils, which can result in unreliable and inconsistent heating. Conversely, PTC heaters rely on heating elements that consist of ceramic stones, based on barium titanate.
The materials in these elements contain properties that enable a PTC heater to self-sense and self-regulate, eliminating the need for external feedback mechanisms. This function acts as a safety feature, rendering the heater unable to overheat.
PTC thermistor materials also have another unique characteristic: They exhibit a positive resistance change as temperatures increase. This means that when the temperature rises, the material's electrical resistance also increases, which serves to limit the current flow.
The result? When temperatures are low, the PTC material allows current to pass easily. Yet, as the threshold temperature rises, the flow becomes restricted.
Understanding NTC Heaters
An NTC heater functions in the opposite manner as a PTC heater.
This type of thermistor exhibits a negative resistance change as the temperatures increase. Then, as the temperatures decrease, current resistance levels strengthen.
These heaters are commonly comprised of sintered semiconductor materials that contain a mix of metal oxides, including:
PTC Heater Applications
Assuming that there is enough power present to heat the PTC beyond its transition temperature (usually between 60°C to 120°C), a PTC heater can be beneficial in a number of industrial applications. Specifically, it works best in projects where an object must be heated to a specific, constant temperature.
In addition, PTC heaters are also preferred for projects that require a sudden change in resistance at a certain temperature. This is because they exhibit a sudden increase in resistance above a defined temperature.
Another benefit? As they're self-regulating, PTC heaters are able to reach a set temperature quickly, then maintain that same heat level with minimal fluctuation. This means no matter how voltage or ambient temperatures may fluctuate, the heater can still operate at the same temperature.
How Do Voltage Fluctuations Affect PTC Heaters?
Consider the distribution systems in North America compared to Europe. In the former, the public grid delivers a voltage output of 120 volts. In the latter, it's 240 volts. Rather than manufacturing different configurations to suit each location, industrial manufacturers can use the PTC heater in both cases, and it will operate at nearly the same temperature despite the voltage difference.
Other common applications for PTC heaters include:
- Self-regulating heaters
- Motor temperature validation
- Overcurrent protection for electronics
- Time delay
- Motor starting
- Liquid level sensing
What are Some NTC Heater Applications?
While PTC heaters are preferred for keeping temperatures constant, NTC heaters are often used to help engineers reach a specific temperature. They're also used in applications that require a change in resistance over a wide temperature range.
When used as a temperature sensor, an NTC heater normally operates in the range of -55°C to 200°C, though they can be used to measure temperatures much higher or lower.
Primary applications for NTC heaters include:
- Temperature sensing
- Temperature control
- Inrush current limiting
- Flow measurement
Why Choose a PTC Heating Element?
Now that we've discussed the primary differences between NTC heaters and PTC heaters, why are PTC models better suited for most applications?
Put simply, they're more reliable.
The heat that these units deliver is safe, consistent, and uniformly distributed.
Unlike NTC heaters, PTC heaters do not require additional temperature regulation or over-temperature protection equipment.
The self-regulating and self-limiting features that PTC heating elements exhibit make them ideal for a range of projects. They also empower industrial engineers to design complex heating solutions for any type of customer. As you design your units, you can set specific locations for your temperature zones to create maximum coverage.
Other personalizations include the ability to adjust watt density with quick modifications. This means you can also add holes and cutouts to create custom patterns as required.
Overall, when you're seeking a heater solution that's cost-effective, dependable and high-performing, a PTC model fits the bill. PTC fan heaters combine the PTC elements with circulating air making them ideal for many applications.
How Do You Find the Right PTC Heating Elements?
Now that we've covered the applications best-suited for both NTC and PTC heating elements, are you ready to purchase a PTC part for your next industrial project?
If so, we're here to help.
We offer a variety of PTC solutions in our online store, including fan heaters, convection heaters, surface heaters, cartridge heaters, finned air heaters, and more. Feel free to browse our inventory to find the specific part you need.
If you have any questions along the way or simply want to learn more about how our products work, reach out to us. We'll help you choose the right part every time.