The Part Number is HEL-7D471K.
The function of this semiconductor is 7mm, 470V, VARISTOR.
Package: Radial Type
Manufacturer: Hongzhi Enterprises
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A varistor is an electronic component that is used to protect electronic devices from overvoltage surges. It is also known as a voltage-dependent resistor (VDR) or a metal-oxide varistor (MOV).
The basic structure of a varistor consists of a ceramic or metal oxide material with a nonlinear resistance characteristic. When the voltage across the varistor reaches a certain threshold, its resistance decreases sharply, allowing a large current to flow through it and diverting the excess voltage away from the device it is protecting.
HEL-7D471K is 470V, VARISTOR. When the voltage across a varistor exceeds a certain threshold (known as the “clamping voltage” or “breakdown voltage”), the varistor’s resistance rapidly decreases, allowing it to conduct excess voltage and divert it away from the protected circuit. This helps prevent damage from voltage spikes and transients that could otherwise harm sensitive components.[…]
Varistors are commonly used in electronic circuits to protect against power surges, lightning strikes, and other voltage spikes that can damage sensitive components. They are also used in power distribution systems, where they help to protect transformers, motors, and other equipment from overvoltage events.