List differences between absolute and secondary instrument.
2 Answers
Sure! Absolute and secondary instruments are two types of measurement tools used in various fields, especially in science and engineering. Here’s a detailed comparison:
### Absolute Instruments
1. **Definition**:
Absolute instruments provide a direct measurement of a physical quantity, such as voltage, current, or mechanical displacement, without relying on any reference measurements. They are calibrated to give accurate readings of the quantity being measured.
2. **Accuracy**:
- **High Accuracy**: Absolute instruments are known for their high accuracy because they are designed to measure the physical quantity directly.
- **Calibration**: They are usually calibrated against known standards or constants to ensure accuracy.
3. **Examples**:
- **Galvanometer**: Measures current directly based on the magnetic field created by the current.
- **Digital Voltmeters**: Directly measure voltage using electronic circuits.
4. **Operation Principle**:
- **Direct Measurement**: These instruments operate based on fundamental physical principles and provide a measurement that reflects the actual value of the quantity being measured.
5. **Usage**:
- **Fundamental Measurements**: Used when precise and fundamental measurements are required, often in scientific experiments and high-accuracy applications.
### Secondary Instruments
1. **Definition**:
Secondary instruments do not measure the physical quantity directly. Instead, they measure a related quantity or use a primary measurement as a reference to infer the value of the quantity being measured.
2. **Accuracy**:
- **Relatively Lower Accuracy**: They are generally less accurate than absolute instruments because their measurements are dependent on a reference or primary instrument.
- **Calibration**: Calibration of secondary instruments depends on the calibration of the primary instruments they are referencing.
3. **Examples**:
- **Thermometers**: While many thermometers measure temperature directly, some use secondary methods such as comparing the expansion of a liquid to a reference scale.
- **Pressure Gauges**: Many pressure gauges use a reference standard to infer the pressure being measured.
4. **Operation Principle**:
- **Indirect Measurement**: Secondary instruments often rely on indirect methods or comparisons to determine the value of the measured quantity. They might use a reference instrument to provide a basis for measurement.
5. **Usage**:
- **Practical Measurements**: Typically used in practical and industrial applications where high precision is not as critical, or where direct measurement methods are impractical.
### Key Differences
1. **Measurement Directness**:
- Absolute instruments provide a direct measurement.
- Secondary instruments infer measurements based on reference or primary instruments.
2. **Calibration Dependency**:
- Absolute instruments are calibrated directly against standards.
- Secondary instruments are calibrated based on the accuracy of primary instruments or references.
3. **Accuracy and Precision**:
- Absolute instruments generally offer higher accuracy and precision.
- Secondary instruments may have lower accuracy and depend on the calibration of primary references.
4. **Application Context**:
- Absolute instruments are preferred in scientific and high-precision contexts.
- Secondary instruments are more commonly used in industrial and practical settings.
Understanding these differences helps in selecting the appropriate instrument based on the requirements of the measurement task and the level of accuracy needed.
### Absolute Instruments
1. **Definition**:
Absolute instruments provide a direct measurement of a physical quantity, such as voltage, current, or mechanical displacement, without relying on any reference measurements. They are calibrated to give accurate readings of the quantity being measured.
2. **Accuracy**:
- **High Accuracy**: Absolute instruments are known for their high accuracy because they are designed to measure the physical quantity directly.
- **Calibration**: They are usually calibrated against known standards or constants to ensure accuracy.
3. **Examples**:
- **Galvanometer**: Measures current directly based on the magnetic field created by the current.
- **Digital Voltmeters**: Directly measure voltage using electronic circuits.
4. **Operation Principle**:
- **Direct Measurement**: These instruments operate based on fundamental physical principles and provide a measurement that reflects the actual value of the quantity being measured.
5. **Usage**:
- **Fundamental Measurements**: Used when precise and fundamental measurements are required, often in scientific experiments and high-accuracy applications.
### Secondary Instruments
1. **Definition**:
Secondary instruments do not measure the physical quantity directly. Instead, they measure a related quantity or use a primary measurement as a reference to infer the value of the quantity being measured.
2. **Accuracy**:
- **Relatively Lower Accuracy**: They are generally less accurate than absolute instruments because their measurements are dependent on a reference or primary instrument.
- **Calibration**: Calibration of secondary instruments depends on the calibration of the primary instruments they are referencing.
3. **Examples**:
- **Thermometers**: While many thermometers measure temperature directly, some use secondary methods such as comparing the expansion of a liquid to a reference scale.
- **Pressure Gauges**: Many pressure gauges use a reference standard to infer the pressure being measured.
4. **Operation Principle**:
- **Indirect Measurement**: Secondary instruments often rely on indirect methods or comparisons to determine the value of the measured quantity. They might use a reference instrument to provide a basis for measurement.
5. **Usage**:
- **Practical Measurements**: Typically used in practical and industrial applications where high precision is not as critical, or where direct measurement methods are impractical.
### Key Differences
1. **Measurement Directness**:
- Absolute instruments provide a direct measurement.
- Secondary instruments infer measurements based on reference or primary instruments.
2. **Calibration Dependency**:
- Absolute instruments are calibrated directly against standards.
- Secondary instruments are calibrated based on the accuracy of primary instruments or references.
3. **Accuracy and Precision**:
- Absolute instruments generally offer higher accuracy and precision.
- Secondary instruments may have lower accuracy and depend on the calibration of primary references.
4. **Application Context**:
- Absolute instruments are preferred in scientific and high-precision contexts.
- Secondary instruments are more commonly used in industrial and practical settings.
Understanding these differences helps in selecting the appropriate instrument based on the requirements of the measurement task and the level of accuracy needed.
Absolute and secondary instruments are two fundamental types of measurement devices used in electrical and other physical measurements. They differ in their design, operation, and application. Here's a detailed comparison between the two:
### 1. **Definition:**
- **Absolute Instruments:**
- These instruments measure the quantity directly and provide the value without requiring any calibration or reference to another instrument. They are designed to derive the measurement based on physical constants and dimensions.
- **Secondary Instruments:**
- These instruments measure the quantity by comparing it with a known standard or by using a calibration that has been established using an absolute instrument or another secondary instrument.
### 2. **Operation Principle:**
- **Absolute Instruments:**
- Operate based on fundamental laws of physics. The measurement is often derived from the geometry, material properties, or the laws of electricity, magnetism, or mechanics.
- **Secondary Instruments:**
- Operate based on a comparison method where the measured quantity is compared with a pre-calibrated value or standard.
### 3. **Examples:**
- **Absolute Instruments:**
- Tangent Galvanometer
- Rayleigh Current Balance
- Ampere’s Weighing Method for current measurement
- **Secondary Instruments:**
- Ammeter
- Voltmeter
- Wattmeter
### 4. **Accuracy:**
- **Absolute Instruments:**
- Generally more accurate because they are based on fundamental measurements. However, they can be complex and sensitive to experimental conditions.
- **Secondary Instruments:**
- Accuracy depends on the calibration and the quality of the reference standard used. They are typically less accurate than absolute instruments but are more practical for regular use.
### 5. **Calibration:**
- **Absolute Instruments:**
- Do not require calibration against a standard. The measurement is derived from the instrument's inherent properties.
- **Secondary Instruments:**
- Require periodic calibration against a standard or absolute instrument to maintain accuracy.
### 6. **Complexity:**
- **Absolute Instruments:**
- Typically more complex in construction and operation, as they involve precise measurements and calculations.
- **Secondary Instruments:**
- Simpler in design and operation, making them easier to use in practical applications.
### 7. **Application:**
- **Absolute Instruments:**
- Used primarily in laboratory settings where high accuracy and fundamental measurements are needed. They are often used to establish standards.
- **Secondary Instruments:**
- Widely used in everyday applications, including industrial and commercial settings, due to their ease of use and practicality.
### 8. **Cost:**
- **Absolute Instruments:**
- Generally more expensive due to their complexity and the precision required in their design and manufacturing.
- **Secondary Instruments:**
- More affordable and widely available, making them suitable for routine measurements.
### 9. **Usage Frequency:**
- **Absolute Instruments:**
- Used less frequently because they are mainly employed for setting standards and in precision laboratories.
- **Secondary Instruments:**
- Used more frequently in everyday measurement tasks in various fields such as electrical engineering, electronics, and industrial applications.
### 10. **Dependence on Reference Standards:**
- **Absolute Instruments:**
- Independent of external reference standards since they measure quantities based on fundamental principles.
- **Secondary Instruments:**
- Depend on external reference standards for calibration and accurate measurement.
### Summary:
- **Absolute instruments** are primarily used for precise, fundamental measurements and do not require calibration against another device, making them essential for establishing standards.
- **Secondary instruments** are widely used in practical applications, depend on calibration against a standard, and are more user-friendly and cost-effective for routine measurements.
### 1. **Definition:**
- **Absolute Instruments:**
- These instruments measure the quantity directly and provide the value without requiring any calibration or reference to another instrument. They are designed to derive the measurement based on physical constants and dimensions.
- **Secondary Instruments:**
- These instruments measure the quantity by comparing it with a known standard or by using a calibration that has been established using an absolute instrument or another secondary instrument.
### 2. **Operation Principle:**
- **Absolute Instruments:**
- Operate based on fundamental laws of physics. The measurement is often derived from the geometry, material properties, or the laws of electricity, magnetism, or mechanics.
- **Secondary Instruments:**
- Operate based on a comparison method where the measured quantity is compared with a pre-calibrated value or standard.
### 3. **Examples:**
- **Absolute Instruments:**
- Tangent Galvanometer
- Rayleigh Current Balance
- Ampere’s Weighing Method for current measurement
- **Secondary Instruments:**
- Ammeter
- Voltmeter
- Wattmeter
### 4. **Accuracy:**
- **Absolute Instruments:**
- Generally more accurate because they are based on fundamental measurements. However, they can be complex and sensitive to experimental conditions.
- **Secondary Instruments:**
- Accuracy depends on the calibration and the quality of the reference standard used. They are typically less accurate than absolute instruments but are more practical for regular use.
### 5. **Calibration:**
- **Absolute Instruments:**
- Do not require calibration against a standard. The measurement is derived from the instrument's inherent properties.
- **Secondary Instruments:**
- Require periodic calibration against a standard or absolute instrument to maintain accuracy.
### 6. **Complexity:**
- **Absolute Instruments:**
- Typically more complex in construction and operation, as they involve precise measurements and calculations.
- **Secondary Instruments:**
- Simpler in design and operation, making them easier to use in practical applications.
### 7. **Application:**
- **Absolute Instruments:**
- Used primarily in laboratory settings where high accuracy and fundamental measurements are needed. They are often used to establish standards.
- **Secondary Instruments:**
- Widely used in everyday applications, including industrial and commercial settings, due to their ease of use and practicality.
### 8. **Cost:**
- **Absolute Instruments:**
- Generally more expensive due to their complexity and the precision required in their design and manufacturing.
- **Secondary Instruments:**
- More affordable and widely available, making them suitable for routine measurements.
### 9. **Usage Frequency:**
- **Absolute Instruments:**
- Used less frequently because they are mainly employed for setting standards and in precision laboratories.
- **Secondary Instruments:**
- Used more frequently in everyday measurement tasks in various fields such as electrical engineering, electronics, and industrial applications.
### 10. **Dependence on Reference Standards:**
- **Absolute Instruments:**
- Independent of external reference standards since they measure quantities based on fundamental principles.
- **Secondary Instruments:**
- Depend on external reference standards for calibration and accurate measurement.
### Summary:
- **Absolute instruments** are primarily used for precise, fundamental measurements and do not require calibration against another device, making them essential for establishing standards.
- **Secondary instruments** are widely used in practical applications, depend on calibration against a standard, and are more user-friendly and cost-effective for routine measurements.