In electronic circuit design and maintenance, distinguishing between varistors and varistor capacitors is often a technical challenge. Although the two components are functionally different, they may be similar in appearance, which requires some specific methods to identify them.
First, we can distinguish these two components from the markings on the circuit board. Usually, the markings of varistor on the circuit board include VSR, VDR, RV, etc., while the capacitor is usually marked with "C". This marking method provides us with a quick way to identify.
Specifically, the type designation of a varistor carries detailed information about its characteristics. Taking JEC14D471K as an example, 14 represents the diameter of the varistor, D represents the round shape, and 471 represents the varistor voltage of 470V. The 1 in the model represents the number of 0s behind it, which is the number raised to the power of 10. K indicates the voltage level, indicating that the voltage range is plus or minus 10% of 470V. In addition, M represents plus or minus 20%, S represents special specifications, J represents plus or minus 5%, etc. These parameters are crucial for understanding the characteristics of varistor.
As for the varistor capacitor, it is a capacitor whose capacitance changes non-linearly with voltage. The charge capacity of this capacitor has saturation characteristics, and its dielectric is usually barium titanate-based ceramics. The production process is similar to that of ordinary ceramic capacitors. This property of varistor capacitors makes them very useful in high-voltage pulse generators, often used to ignite gas discharge lamps such as fluorescent lamps or flammable gases.
Another way to differentiate between the two components is to test them with a multimeter. During the test, if there is resistance at both ends, then the component is a varistor; if the resistance is infinite, it is a varistor. This testing method provides a simple and effective way to identify these two commonly used but easily confused components.
To sum up, through the markings on the circuit board, the model naming rules and the multimeter test, we can effectively distinguish the varistor and the varistor, so as to more accurately apply these key components in the design and maintenance of electronic circuits.