Terminology » RF Components » Barrier vs. Isolator: Key Differences Explained

Barrier vs. Isolator: Key Differences Explained

intrinsic safety electrical isolation zener barrier galvanic isolator circuit

This article clarifies the distinctions between barriers and isolators, particularly in the context of intrinsically safe instruments and circuits. We’ll use zener barriers and galvanic isolators as examples to illustrate these differences.

A barrier aims to limit the loop current to a safe level, preventing sparks in hazardous environments. On the other hand, an isolator facilitates signal interfacing between circuits with different common-mode voltages, ensuring electrical isolation.

Let’s delve into a detailed comparison:

Zener Barriers vs. Galvanic Isolators: A Comparative Analysis

Feature	Barrier (Zener)	Isolator (Galvanic)
Complexity	Simple	Complex
MTBF (Mean Time Between Failures)	Low	Higher
Application	Suitable when front-end engineering demands are high	Used in application-specific requirements
Versatility	Versatile	Less versatile
Dissipation	Low	High (around 2 VA)
Powering	Loop-powered	Separate power supply required
Voltage Constraints	Ideal where restricted voltage is available in hazardous areas	Suitable where higher voltage is available in hazardous and safe areas
Packing Density	High	Low
Cost	Lower	Higher
Frequency Response	Good	Limited
Accuracy & Linearity	Higher	Lower
System Impact	Imposes zero-volt level on the system	Provides complete isolation between signals
Surge Vulnerability	More vulnerable to lightning and other surges	Less vulnerable to lightning and other surges

In essence, barriers offer a simpler and more cost-effective solution when voltage limitations are a primary concern. Isolators, while more complex and expensive, provide complete electrical isolation and are less susceptible to surges. The choice between them depends on the specific requirements and constraints of the application.