Types of errors in measuring instruments:
A) Gross error: These are due to mistakes on the part of person using the instrument.
B) Systematic Error:
i) Instrumental Error: These errors are caused due to the mechanical structure of measuring instrument. a) Inherent shortcomings of instruments: Instrument may read too low or too high. b) Improper use of instruments: Improper handling e.g. overloading, overheating, failure to adjust zero, use of high resistance leads. c) Loading effect: cause distortion in original signal.
ii) Environmental Error: These are because of surrounding conditions such as temperature, pressure, humidity, dust, vibrations, or external magnetic fields or electrostatic fields.
iii) Observational Error: Parallax errors, incorrect multiplying factor.
C) Random error: These persist even after gross and systematic errors are removed.