In electronic components, there is a class of resistors called varistors, which is a nonlinear volt-ampere characteristics of the resistor, sensitive to voltage, in a certain voltage range, the resistance value of the varistor will change with the change of voltage. It is made of semiconductor material and belongs to semiconductor components. Varistor plays overvoltage protection and lightning protection in the circuit, when the voltage in the circuit is too large, varistor voltage clamp to absorb excess current, protect the circuit and other electronic components, so it is widely used in power systems, security systems, household appliances and other fields. The following is mainly a brief analysis of the varistor for your reference.

Varistor is a kind of overvoltage protection device with nonlinear volt-ampere characteristics, and its material is semiconductor, which is a special semiconductor resistor. Varistors limit the voltage in the circuit and protect the circuit and other components behind the circuit. The resistance value of the varistor is related to the voltage, and the resistance value of the varistor is infinite when the circuit voltage is normal. When the circuit voltage is higher than the voltage of the varistor, the resistance value becomes smaller, the varistor switch is in a closed state, and the current in the circuit becomes larger. When it passes through the varistor, the varistor absorbs the excess current and clamps the voltage to a fixed value to protect the circuit and other electronic components.

If the components are connected in parallel between the power supply, the circuit is a parallel circuit. The characteristic is that the current of the main road is divided into several parts in the branch, and the various components in the several branches are respectively flowed through.

If the components in the circuit are connected one by one in sequence, the circuit is a series circuit, characterized by: the current flowing through one component also flows through another. In a series circuit, because the current path is only one, the current flowing from the positive terminal of the power supply will flow through each electrical appliance one by one and return to the negative terminal of the power supply.

(1) Detect the overcurrent protection function. Overcurrent protection is the circuit with the most faults in VFD control system, and it is also the most important circuit to protect the main circuit components and devices. Generally, by simulating overload and adjusting the action value, the test can reliably operate under the set overcurrent value and cut off the output.

Circuit introduction: The circuit through which the current flows is called a circuit. The simplest circuit consists of components such as power supply, load, wires and auxiliary devices connected in a certain way to provide the overall path for the flow of charges.

Components of a hybrid microcircuit, such as monolithic deposited or screen-printed passive components, substrates, discrete or integrated electronic devices, including chips, chip components, and other microcomponents, as well as mechanical parts, such as shells, covers, and all components that act on the hybrid microcircuit;

Self-restoring fuse PTC is an overcurrent electronic protection element. The passive circuit component is made of high molecular organic polymer doped with conductive particles under high pressure, high temperature and vulcanization reaction. The self-restoring fuse is an overcurrent protection element composed of a specially treated polymer resin and electrically conductive particles distributed inside.

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