PCB thermistors are essential components in printed circuit boards, designed to measure and monitor temperature changes by converting thermal energy into an electrical signal. These resistors are based on the principle of varying electrical resistance with temperature, making them highly useful in a wide range of applications where temperature sensing is required.

There are two main types of thermistors used in PCBs: negative temperature coefficient (NTC) and positive temperature coefficient (PTC) thermistors. NTC thermistors have a resistance that decreases as the temperature increases. This characteristic makes them ideal for applications such as temperature compensation in circuits, where changes in temperature can affect the performance of other components. For example, in power supply circuits, NTC thermistors can be used to limit inrush current during startup, protecting the circuit from excessive current spikes. PTC thermistors, on the other hand, have a resistance that increases with temperature. They are often used as self - resetting fuses in PCBs, as an increase in current due to a short circuit or overload will cause the PTC thermistor's temperature to rise, increasing its resistance and reducing the current flow, thus protecting the circuit.

When integrating thermistors into PCBs, several factors need to be considered. The placement of the thermistor on the PCB is crucial, as it should be positioned in an area where it can accurately sense the temperature of the components or environment it is intended to monitor. Additionally, the thermal connection between the thermistor and the target area must be optimized to ensure fast and accurate temperature response. Signal conditioning circuits are often required to convert the thermistor's resistance change into a usable electrical signal, which can then be processed by a microcontroller or other circuitry.

In applications such as computer motherboards, thermistors are used to monitor the temperature of the CPU and other critical components, triggering fans to increase their speed when necessary to prevent overheating. In automotive electronics, they play a vital role in engine management systems, monitoring coolant and oil temperatures. In industrial control systems, thermistors are used to maintain the temperature of manufacturing processes within specified ranges. As the demand for precise temperature control and monitoring in electronic devices continues to grow, the importance of PCB thermistors in ensuring the reliability and performance of these systems cannot be overstated.