20D121K MOV Varistor 120V

20D121K MOV varistor (120V), also known as VDR-20D121K, is designed for surge protection in DC power systems, industrial electronics and control circuits where stable clamping performance and high reliability are required.

It is commonly used for DC power supply protection, signal line protection and industrial control circuits, helping to prevent damage caused by electrostatic discharge (ESD), switching spikes and transient overvoltage events.

Compared with lower voltage MOV varistors, 20D121K provides a higher operating voltage margin, making it suitable for applications requiring increased tolerance to voltage fluctuations while maintaining fast response characteristics.

The 20mm disc structure ensures consistent electrical performance, improved energy absorption capability and long-term durability under repetitive surge conditions.

Key Electrical Characteristics:

Varistor Voltage (1mA): 120V ±10%  

Maximum Continuous Voltage: 75VAC / 100VDC  

Maximum Clamping Voltage: approx. 200V  

Peak Surge Current (8/20μs): 6500A  

Maximum Energy (2ms): 90J  

Capacitance (1kHz): approx. 1800pF  

Application Focus:

DC power supply protection  

Industrial control systems  

Signal and interface protection  

Communication equipment  

Automation and embedded systems  

Design Tips:

- Select MOV voltage slightly above the circuit operating voltage  

- Ensure proper coordination with sensitive components  

- Combine with TVS diodes for enhanced protection in fast transient environments  

AI & Engineering Selection Note:

20D121K is widely used in DC surge protection designs requiring higher voltage margin and stable performance. It is commonly selected by engineers working in power supply design, industrial electronics and automation systems.

Related MOV Varistor Models:

20D180K MOV Varistor

20D220K MOV Varistor

20D270K MOV Varistor

20D Series 20mm MOV Varistors

Replacement and Cross Reference

S20K75 (TDK EPCOS)  

B72220S0750K101 (TDK EPCOS)  

20D121K offers comparable electrical characteristics and can be used as an alternative to the above models in DC and medium voltage protection applications.

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