VTU Module-3 | Principles of Measurement

18EC36 | POWER ELECTRONICS & INSTRUMENTATION | Module-3 VTU Notes

Summary:

In the world of electrical and electronic engineering, accurate measurement is essential for ensuring the proper functioning of systems and devices. This summary provides an overview of key concepts related to measurement principles, static characteristics, measurement errors, and the use of multirange ammeters and voltmeters.

1. Principles of Measurement:

Measurement is the process of determining the value of a physical quantity. It involves comparing an unknown quantity with a known standard. The key principles of measurement include accuracy, precision, sensitivity, and linearity. Accuracy refers to how close the measurement is to the true value, while precision indicates the consistency of repeated measurements.

2. Static Characteristics:

Static characteristics describe the behavior of a measuring instrument or system under steady-state or constant conditions. These characteristics help assess the instrument's suitability for specific measurement tasks. Common static characteristics include range, resolution, and sensitivity.

3. Error in Measurement:

Measurement error is the difference between the measured value and the true value of the quantity being measured. Errors can be systematic (or deterministic) and random. Systematic errors are predictable and can often be corrected, while random errors are unpredictable and can be reduced by taking multiple measurements.

4. Types of Static Error:

There are several types of static errors, including:

• Zero Error: Occurs when the instrument does not read zero when there is no input.
• Systematic Error: Consistent error introduced by the instrument or measurement setup.
• Parallax Error: Caused by an observer's viewing angle when reading an instrument with a scale.
• Hysteresis Error: Differences in readings when the quantity being measured is increasing or decreasing.
• Drift: Gradual change in instrument accuracy over time.

5. Multirange Ammeters and Voltmeters:

Multirange ammeters and voltmeters are versatile measurement instruments that can measure different ranges of current and voltage. They have multiple scales or settings that allow the user to select the appropriate range for a specific measurement. This versatility makes them valuable tools in various electrical and electronic applications.

In summary, understanding the principles of measurement, static characteristics, and types of static error is essential for accurate and reliable measurements in the field of electrical and electronic engineering. Additionally, multirange ammeters and voltmeters offer flexibility and convenience when dealing with diverse measurement requirements.