I. Overview Power isolation sensors/transmitters are small, high-performance electrical signal measurement components or modules developed for power detection (monitoring) in engineering applications, aiming to improve the overall anti-interference capability of the system. Power isolation sensors/transmitters can isolate, measure, and transform electrical parameters such as high current, high voltage, power, frequency, phase angle, and electricity consumption in the field. They can also isolate, amplify, and transform various weak signals (such as various bridge signals), conditioning them to convert them into analog signals such as voltage, current, and frequency conforming to international standards, or into digital signals, switch status signals, etc. These output signals can be connected to traditional pointer instruments, as well as modern digital automatic control instruments, various A/D converters, and computer systems, thus forming a highly reliable industrial detection (monitoring) or control system. Because power isolation sensors do not require secondary development work from users, high voltage or high current signals can be directly connected to the product (through terminals, pins, or through-hole inputs) to obtain the corresponding output signals. Therefore, as a module for signal conditioning, isolation, and conversion, the power isolation sensor is an ideal transmitter product in industrial control and data acquisition systems. With the continuous development of science and technology, the requirements for power isolation sensors in industrial control or detection (monitoring) systems are becoming increasingly stringent, especially in terms of product stability, detection accuracy, and functionality. The working principle of the power isolation sensor is briefly described below for your reference. II. Basic Working Principle of Power Isolation Sensors Since the detected objects of power isolation sensors are mainly current and voltage signals, the detection principles of current and voltage signals are mainly introduced below. 1. AC Signal Detection Principle AC signals are further divided into AC voltage and current signals. Figure 1 shows the block diagram of the AC current signal detection principle, and Figure 2 shows the block diagram of the AC voltage signal detection principle. The signal is isolated by CT and PT. Current is input via a through-hole method, and voltage is input via a terminal wiring method. Figure 1: Block Diagram of AC Current Signal Product Principle Figure 2: Block Diagram of AC Voltage Signal Product Wherein, CT is a current transformer, PT is a voltage transformer, and the output is generally 0-5V or 4-20mA. 2. DC Signal Detection Principle Diagram 3. DC Signal Product Principle Block Diagram DC signals are divided into DC voltage and DC current. DC current is generally sampled through a resistor, while DC voltage is generally processed by reducing the voltage using a resistor. An isolated power supply powers the preamplifier. There are two common isolation principles: one uses linear optocoupler isolation technology, and the other uses modulation and demodulation technology. As can be seen from the above principle block diagram, whether it is an AC signal or a DC signal, the input and output are completely isolated. Generally, the input signals in the field are large current, high voltage, or small signals. Thus, the power isolation sensor can completely isolate the field signal from the low-voltage data acquisition system, avoiding interference from strong signals and improving system reliability. III. Conclusion The above briefly introduces the basic working principle of the power isolation sensor. Since there are many types of power isolation sensors and many methods for implementing them, this article only provides a brief introduction to the principle of power isolation sensors. This is for reference only, and we hope to jointly promote the development of power isolation sensor technology.