Measurement and Instrumentation - Attracted Disc Type Voltmeter
1 Answer
An Attracted Disc Type Voltmeter is a type of analog electrical instrument used for measuring voltage in a circuit. It belongs to the category of electrostatic instruments and operates based on the principle of the attraction between charged plates. Here's a basic explanation of how it works:
Construction: The attracted disc type voltmeter consists of two main components: a movable disc and fixed plates. The movable disc is suspended between two fixed parallel plates. The disc is attached to a spindle that allows it to rotate freely.
Principle of Operation: When a voltage is applied across the fixed plates, a potential difference is created between them. Due to this potential difference, the movable disc experiences an electrostatic force of attraction towards one of the fixed plates. The magnitude of this force is directly proportional to the potential difference (voltage) applied across the plates.
Deflection Mechanism: As the disc is attracted towards one of the plates, it rotates around its axis. This rotation is proportional to the force acting on the disc, which in turn is proportional to the applied voltage. The degree of rotation of the disc is used to indicate the magnitude of the voltage being measured.
Calibration: To make the attracted disc voltmeter a useful measurement instrument, it needs to be calibrated. Calibration involves determining the relationship between the angle of rotation of the disc and the actual voltage applied across the plates. This calibration can be achieved by comparing the voltmeter readings with known standard voltage sources.
Accuracy and Limitations: The accuracy of an attracted disc voltmeter depends on factors like the mechanical design, the uniformity of the electric field between the plates, and the sensitivity of the deflection mechanism. It may not be as accurate as modern digital voltmeters, but it can provide reasonably accurate measurements for many applications.
Advantages and Disadvantages: The attracted disc type voltmeter has the advantage of being a simple and rugged instrument suitable for measuring DC voltages. However, it may have limitations in terms of accuracy, sensitivity to external electromagnetic fields, and readability compared to digital instruments.
It's worth noting that with advancements in technology, digital voltmeters (DVMs) have become more popular due to their higher accuracy, ease of use, and ability to measure a wide range of voltages. Nonetheless, attracted disc type voltmeters are part of the history and development of electrical measurement instruments.
Construction: The attracted disc type voltmeter consists of two main components: a movable disc and fixed plates. The movable disc is suspended between two fixed parallel plates. The disc is attached to a spindle that allows it to rotate freely.
Principle of Operation: When a voltage is applied across the fixed plates, a potential difference is created between them. Due to this potential difference, the movable disc experiences an electrostatic force of attraction towards one of the fixed plates. The magnitude of this force is directly proportional to the potential difference (voltage) applied across the plates.
Deflection Mechanism: As the disc is attracted towards one of the plates, it rotates around its axis. This rotation is proportional to the force acting on the disc, which in turn is proportional to the applied voltage. The degree of rotation of the disc is used to indicate the magnitude of the voltage being measured.
Calibration: To make the attracted disc voltmeter a useful measurement instrument, it needs to be calibrated. Calibration involves determining the relationship between the angle of rotation of the disc and the actual voltage applied across the plates. This calibration can be achieved by comparing the voltmeter readings with known standard voltage sources.
Accuracy and Limitations: The accuracy of an attracted disc voltmeter depends on factors like the mechanical design, the uniformity of the electric field between the plates, and the sensitivity of the deflection mechanism. It may not be as accurate as modern digital voltmeters, but it can provide reasonably accurate measurements for many applications.
Advantages and Disadvantages: The attracted disc type voltmeter has the advantage of being a simple and rugged instrument suitable for measuring DC voltages. However, it may have limitations in terms of accuracy, sensitivity to external electromagnetic fields, and readability compared to digital instruments.
It's worth noting that with advancements in technology, digital voltmeters (DVMs) have become more popular due to their higher accuracy, ease of use, and ability to measure a wide range of voltages. Nonetheless, attracted disc type voltmeters are part of the history and development of electrical measurement instruments.