The 7550A is an ammeter with a measurement range from 1µA to 250A. The voltage on the shunt is switched to the internal four-and-a-half-digit AC and DC ammeter directly displayed by the five file-bit buttons and on the external output terminal. AC and DC current values with high accuracy and resolution.

Shunt resistors and current transformers each offer valuable advantages for smart meter design, but they serve different design priorities. Shunt resistors often stand out for economy, direct sensing, and compact integration. Current transformers often stand out for isolation, magnetic sensing structure, and suitability in certain robust metering architectures. The better choice depends on the actual meter platform, including cost target, thermal strategy, safety structure, integration method, and long-term reliability goals. By evaluating both sensing methods from a full system perspective, smart meter developers can make a more practical and more reliable design decision.