TH MOV means a through-hole metal-oxide varistor, most commonly a radial leaded disc MOV. It is connected in parallel with the line or circuit being protected and conducts strongly during an overvoltage transient.
This page is the component hub for through-hole MOV structure, ratings, applications and selection resources. For the full introduction, read What Is a Through-Hole MOV?.
Overview
A typical through-hole MOV uses a sintered zinc-oxide ceramic disc with electrodes on both faces, radial metal leads and an insulating coating. Disc MOVs are widely used where higher surge current and energy capability are required and leaded assembly is acceptable.
Codes such as 7D, 10D and 14D generally indicate a nominal disc-size class. Markings such as 471K commonly encode a varistor-voltage class and tolerance, but the exact interpretation must be confirmed in the manufacturer’s datasheet. A size or marking alone does not establish the safe continuous operating voltage or surge endurance.
Main Advantages
- Broad range of continuous-voltage and surge-energy classes
- Simple bidirectional two-terminal protection
- Established use in power supplies, appliances and industrial equipment
- Multiple disc sizes for different pulse and space requirements
- Visual markings that support production identification when verified against the datasheet
Typical Applications
- Alternating-current (AC) mains inputs after appropriate fuse coordination
- Power supplies, adapters and lighting drivers
- Industrial control and motor-related switching environments
- Appliances, charging equipment and power distribution modules
- Telecommunication and renewable-energy power interfaces
- Direct-current (DC) buses when the selected rating covers the actual voltage and transient
Specifications to Compare
Review maximum continuous AC and DC voltage, varistor voltage at the stated test current, clamping voltage at the stated pulse current, peak surge current, energy, pulse waveform, repetitive-pulse curves, rated power, capacitance, leakage, temperature derating and failure mode.
For power-line use, also consider fuse or thermal-disconnect coordination, abnormal overvoltage, creepage, clearance and applicable safety requirements. A MOV limits a transient; it does not automatically provide safe disconnection during a sustained fault.
Series and Model Selection
Do not select only by a familiar code such as 10D471K. First establish the maximum normal voltage and the required surge test. Then compare worst-case clamping level, pulse endurance, disc size, lead spacing, coating, operating temperature and qualification.
For a cross-reference or project review, provide the original part number, AC/DC voltage, test standard, waveform, source impedance or current, pulse count, maximum allowable clamping voltage, disc diameter and lead spacing through Ask UBAEC.
Downloads
Verified datasheets, marking guides and derating resources will be added here. Use the current manufacturer datasheet and system-level test as the final design authority.