What are the functions and options of SMD Patch varistors?

SMD chip varistoris an electrical component widely used in our life. The use of resistors effectively protects our circuits and makes our circuits more stable. There are many kinds of resistors, so how to choose a rheostat for measurement? Now let's take a look

SMD capacitors are mainly used to reduce harmful atmospheric overvoltage and working voltage, and can effectively protect the system or equipment:

In the power industry, pressure-sensitive materials are commonly used to make lightning arrester valves. High-voltage insulators made of zinc oxide pressure-sensitive materials can not only insulate, but also realize transient overvoltage protection.

In electronic circuits, it has overvoltage protection, lightning protection, surge current suppression, peak pulse Functions such as absorption, amplitude limiting, high-voltage arc extinguishing, noise elimination, protection device, etc

Selection of SMD chip varistor

According to the requirements of specific circuit, the key is to accurately select the nominal voltage value. General selection method: the nominal voltage of the rheostat should be 2~2.5 times of the applied voltage at both ends of the rheostat. In addition, attention should also be paid to the selection of SMD patch varistor with small resistance temperature coefficient to ensure the stability of the circuit. The specific model selection is as follows:

(1) The overvoltage protection circuit of the frost-free refrigerator can select Myg4SMD patch varistor

(2) For the overcurrent of semiconductor devices, the type I protection circuit can be SMD patch varistors such as MyD series, myl series, MYH, myg20, etc

(3) SMD patch varistors such as myh3-205, myh3-208, myh3-212 can be selected for color TV overvoltage protection circuit

(4) Myg series, my21 series and my31 series SMD patch varistors can be selected for overvoltage protection circuits of electronic circuits, electrical equipment and power systems

1. The rheostat should be measured separately

Generally, theSMD patch varistorhas good nonlinearity, that is, the resistance decreases with the increase of applied voltage. It has bidirectional current characteristics. When measuring, set the multimeter at R × At 1K, measure the forward and reverse insulation resistance between the two pins. The resistance is infinite, otherwise it means that the leakage current is large. If the measured resistance is too small, it indicates that the rheostat is damaged and cannot be used. A digital multimeter can be used to measure the rheostat

2.SMD patch varistoronline measurement

When measuring the rheostat separately, use the R measured at 1K gear × Resistance, forward and reverse resistance values are infinite. When measuring online, if there is no parallel component, R × The resistance of 1K gear measured online is still infinite. If the resistance is too small, the rheostat is damaged and cannot be used. If other components are connected in parallel, the resistance measured online is not the actual resistance of the capacitor, but the resistance in parallel with other components, not infinite

This is the function, selection and measurement of SMD capacitor. The correct selection of resistors will help us to better build circuits and ensure that resistors can play a better role