Which is Better for Inrush Current: PTC Thermistors or NTC Thermistors?
March 21, 2023 at 10:00 PM

As the demand for power components increases, so does the need for reliable, efficient solutions. Thermal protection is one of the most important aspects of any power system, and thermistors are a vital element in achieving this. Choosing between two types of thermistors—PTC (positive temperature coefficient) and NTC (negative temperature coefficient)—can be tricky since both offer distinct advantages and disadvantages when used to manage inrush current. NTC’s and PTC’s benefits are different and can support your needs differently. Let’s take a closer look at each type of thermistor to better understand why they are best suited for specific applications.

PTC Benefits vs. NTC Benefits

What Are PTC and NTC Thermistors?

Thermistors are resistive temperature-sensing devices that measure the resistance of a material within an electrical circuit. PTC thermistors have a positive temperature coefficient, meaning as they get warmer, their resistance increases; conversely, NTC thermistors have a negative temperature coefficient, which means their resistance decreases as they become warmer.

PTC Thermistors for Inrush Current

The primary advantage of using PTC thermistors for inrush current is their ability to limit power surges by absorbing excess energy from the circuit. Simply put, if too much energy is drawn from the main supply line during startup or due to other unexpected sources, the PTC will absorb it—in effect, "resetting" itself after the surge dissipates. This makes it an ideal solution for protecting sensitive components from damage due to overloads or short circuits.

PCT thermistors also provide inherent self-healing capabilities; when overcurrent conditions occur, the device will automatically shut off before resetting itself once the current has dropped below acceptable levels. The automatic shutoff eliminates the need for manual intervention or expensive replacement parts in case of an overcurrent issue.

NTC Thermistors For Inrush Current

NTC thermistors are primarily used to control inrush current through active monitoring and limiting techniques such as soft start circuits or pulse width modulation (PWM). This limits peak currents while also providing added protection against overloads and surges, thanks to its negative thermal coefficient properties. Additionally, using an NTC can greatly reduce overall energy consumption compared to other alternatives, such as contactor relays or fuses, because it requires less voltage drop across its terminals when activated.

Weigh the Difference: PTC Benefits vs. NTC Benefits

When dealing with inrush current, there are many factors to consider before choosing which type of thermistor is best suited for your application; however, both PCT and NTC offer distinct advantages that make them ideal solutions depending on your specific needs.

While PCT offers great self-healing properties that can help protect against overloads or short circuits without requiring manual intervention or replacement parts, NTC offers more efficient active monitoring techniques such as soft start circuits or pulse width modulation (PWM). Ultimately, it comes down to evaluating your application needs and determining which type will provide you with the best possible performance while still keeping operational costs low. With careful consideration and research into each option’s unique benefits and drawbacks, you can decide which type of thermistor is right for you.

For guidance and support when making decisions about your manufacturing equipment, contact Sisler Companies. Sisler’s experts can advise on the best electrical solutions, no matter your needs. Get in touch today to learn more.