What products use varistors?

As a key overvoltage protection component, varistors are widely used in various electronic and electrical products due to their nonlinear volt ampere characteristics (resistance drops sharply when voltage exceeds the threshold) and fast response capability (nanosecond level). According to the application scenarios and technical requirements, its core application areas can be classified into the following five categories:
1、 Household appliances
Varistors are mainly used for power input protection, to resist transient overvoltages such as grid fluctuations and lightning induction
Large household appliances:
TV, air conditioner, refrigerator, washing machine - protect power module and motor drive circuit.
Induction cookers and microwave ovens - suppress switch surges and electromagnetic interference.
Small electronic devices:
Mobile phone charger, computer power adapter - prevent internal IC damage from electrical sparks and voltage spikes during insertion and removal.
2、 Communication and network equipment
Regarding surge protection requirements for signal and power lines:
Terminal devices:
Routers, switches, base stations - protect communication ports (such as RJ45 interfaces) from lightning induced voltage surges.
Fiber optic transceiver, modem - suppresses EFT (electrical fast transient) interference introduced by power lines.
infrastructure:
Communication room distribution cabinet - as a primary lightning protection module, it absorbs surge energy from the power grid side.
3、 Power system and industrial equipment
Provide reliable protection in high-pressure and high-energy environments:
Power device:
Surge arrester valve plate (zinc oxide varistor ceramic) - used in power transmission and transformation systems to limit operating overvoltage and lightning overvoltage.
Smart meter - protects RS485 communication interface and power input level.
Industrial control system:
PLC (Programmable Logic Controller), frequency converter - protects I/O modules and motor drivers from the impact of inductive load back electromotive force.
CNC machine tool power supply - suppresses grid harmonics and switch surges.
4、 Automotive Electronics
Dealing with transient interference in complex electrical environments of vehicles:
Power system:
Battery Management System (BMS) - prevents overvoltage damage to the battery pack during charging and discharging processes.
Motor controller (such as EPS, air conditioning compressor) - absorbs the reverse electromotive force generated by motor start stop.
In car electronics:
ECU (on-board computer) power module - suppresses voltage spikes caused by ignition coils and relay on/off.
Charging pile - lightning protection design for AC/DC input terminal.
5、 Infrastructure and public facilities
Ensure the stable operation of public facilities:
Security system:
Monitoring camera power supply, access control controller - prevent lightning strikes from entering through network cables or power lines.
New energy equipment:
Photovoltaic inverters and wind power converters - DC bus side surge absorption to protect power devices.
Civil facilities:
Smart socket and LED driver power supply - suppress the impact of grid fluctuations on sensitive loads.
The core value of varistors lies in their role as "circuit safety valves", with applications covering five major fields: home appliances, communications, power, automobiles, and industry. When selecting, it is necessary to focus on matching the pressure-sensitive voltage (higher than the peak working voltage), current capacity (suitable for surge level), and residual voltage ratio (lower than the withstand voltage value of the protected device). With the popularization of intelligent devices, their applications in emerging scenarios such as new energy and the Internet of Things will continue to expand.