RFBarrier vs. Isolator: Key Differences Explained
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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.
