Varistors can be used as suppressors to protect devices and circuits from transient abnormal voltages including an ESD (electrostatic discharge) and a lightning surge. <br>For protection from a relatively large surge current (100A to 25kA), leaded disk varistors and SMD disk varistors are suitable. For protection from a larger surge current (approximately 25kA or more), block varistors, and strap varistors are suitable.<br>
This article describes surge protection device applications for LED lighting system, inductive loads such as motors, motor with an electromagnetic brake, SSR (solid-state relay), load dump and field decay, joint boxes and power conditioners of solar power generation systems, important devices using a lightning transformer, and high-energy surge in industrial devices.