Basic Electricity - Senior Secondary 2 - Measuring instruments: Errors II

TERM: 2^ND TERM

WEEK THREE

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: BASIC ELECTRICITY

Topic: MEASURING INSTRUMENTS: ERRORS II

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

I.) State the functions of the damping device in measuring instrument

II.) State the functions of the pointer in measuring instrument

III.) Identify the sources of Errors in Measuring Instruments

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

MEASURING INSTRUMENTS: ERRORS II

Functions of the damping device and the pointer in measuring instruments

1. Damping Devices: Damping devices, such as dashpots or air damping systems, are used to reduce oscillations or vibrations in the moving parts of the measuring instrument. This ensures that the pointer or indicator settles quickly and accurately to the measured value, providing stable readings.
2. Pointer: The pointer is the part of the measuring instrument that indicates the measured value on the scale. It moves in response to changes in the quantity being measured and provides a visual reference for the user to read the value accurately. The pointer is usually designed to be precise, clear, and easily readable to facilitate accurate measurements.

Sources of Errors in Measuring Instruments

1. Instrument Drift: Gradual changes in the instrument's calibration or accuracy over time, leading to inaccuracies in measurements.
2. Environmental Factors: Variations in temperature, humidity, or electromagnetic interference can affect the performance of measuring instruments.
3. Instrument Loading: The act of connecting the measuring instrument to a circuit can alter the behavior of the circuit, leading to measurement errors.
4. Operator Errors: Incorrect operation, improper calibration, or misinterpretation of readings by the user can introduce errors into measurements.
5. Mechanical Wear: Wear and tear on moving parts, such as pointers or switches, can affect the reliability and accuracy of measurements over time.
6. External Forces: Vibrations, shocks, or other external forces acting on the instrument can cause fluctuations in readings or damage to sensitive components.

 EVALUATION: 1. State the function of the damping device in measuring instrument

2. State the function of the pointer in measuring instrument
3. Identify 5 sources of Errors in Measuring Instruments

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively