What Is a Surge Resistor?

What Is a Surge Resistor? Function, Types, and Key Applications

Introduction: Surge resistors are critical components in electronic circuits, protecting sensitive devices from voltage spikes and transient surges. But how exactly do they work, and what types are best for your application? This guide explains the fundamentals of surge resistors, compares different types, and provides data-driven insights to help you select the right one.

How Does a Surge Resistor Work?

A surge resistor limits sudden voltage spikes by dissipating excess energy as heat. Unlike a varistor, which clamps voltage, it provides controlled resistance to suppress transient surges in:

• Power supplies

• Motor drives

• Telecommunication circuits

Types of Surge Resistors (Comparison Table)

Key Applications in Electronics

Surge resistors are used in:

• Solar inverters – Prevent damage from lightning-induced surges

• LED drivers – Extend lifespan by suppressing voltage fluctuations

• Industrial motor controls – Reduce downtime from electrical noise

How to Choose the Right Surge Resistor?

Follow these steps for optimal surge resistor selection:

1. Check voltage rating – Must exceed system’s max surge voltage

2. Verify power dissipation – Use formula: P = I²R

3. Consider environment – High temps require derating

Common Problem: Overheating & Solutions

Problem: Surge resistors often overheat due to:

• Insufficient power rating

• Poor ventilation

• Frequent surge events

Solutions:

Final Tip: For high-voltage surge resistors, always test with a multimeter after installation.