The document discusses various types of errors in measurement, including gross, random, and systematic errors, along with their specific causes such as instrumental, environmental, and observational factors. It highlights corrective measures to reduce these errors, such as maintaining constant conditions and using shielding techniques. Additionally, it covers the dynamic characteristics of measurement systems, including speed of response, fidelity, lag, and dynamic error.

1. Types of Errors

2. • Gross Errors
• Random Errors
• Systematic Errors
– Instrumental Errors
– Environmental
– Observational

3. • Instrumental Errors:
• Due to inherent shortcomings in the instrument:
Due to mechanical structure, construction,
calibration or operation of instruments.
• Due to misuse of instruments: Failure to adjust
zero of instruments, poor initial adjustments,
using leads of too high resistance.
• Due to loading effects of instruments:

4. Environmental Errors:
• Errors due to temperature effect, humidity, dust,
external magnetic or electrostatic field.
Corrective measures:
• Try to keep the conditions constant.
• Use material which is immune to these effects.
• Using techniques which eliminates these effects.
• use air conditioner
• sealing certain component in the instruments
• use magnetic shields

5. Observational error
- introduce by the observer
- most common : parallax error and estimation
error (while reading the scale)
• Eg: an observer who tend to hold his head
too far to the left, while reading the position
of the needle on the scale.

6. Random Errors
• Random errors in experimental measurements
are caused by unknown and unpredictable
changes in the experiment.
• These changes may occur in the measuring
instruments or in the environmental conditions.
Examples of causes of random errors are:
• electronic noise in the circuit of an electrical
instrument,
• irregular changes in the heat loss rate from a
solar collector due to changes in the wind.

7. • Look at this ammeter:
• What can you say?

8. • Look at this voltmeter:
• Zero errors What is the first thing to do?
• Use a screwdriver here to adjust the pointer.

9. • A spring balance: Zero errors
• Over a period of time,
the spring may weaken,
and so the pointer

10. Dynamic Characteristics
The dynamic characteristics of a measurement
system are:
1)Speed of response
2)Fidelity
3)Lag
4)Dynamic error

11. Speed of response
It is defined as the rapidity with which an
instrument, responds to the changes in the
measured quantity.
• It shows how active and fast the system is.
• Speed measuring instruments:-

12. Fidelity
It is defined as the degree to which a
measurement system is capable of faithfully
reproducing the changes in input, without any
dynamic error.

13. Measuring lag
Every system requires its own time to respond to the
changes in input. This time is called as lag.
• It is defined as the retardation or delay, in the response
of a system to the changes in the input.
• The lags are of two types:
1. Retardation lag:
• As soon as there is a changes in the measured quantity,
the measurement system begins to respond.
2. Time delay:
• The response of the measurement system starts after a
dead time, once the input is applied. They cause
dynamic error.

14. Dynamic error
• It is the difference between the true value of
the quantity that is to be measured, changing
with time and the measured value, if no static
error is assumed.