1. Method error

It refers to the error caused by improper modification and simplification of some classical measurement methods due to the imperfect measurement methods used and the imprecise theoretical basis, that is, the error caused by all the factors that are not reflected in the expression of the measurement results, and in fact, these factors play a role, which is also called theoretical error.

2. Instrument, instrument error

Errors introduced by the instrument, the instrument itself, and its accessories, due to the electrical or mechanical imperfections of the instrument. For example: the standard resistance in the bridge, the probe line of the oscilloscope, etc., contain errors. Errors caused by zero offset, calibration inaccuracy, and nonlinearity of instruments and instruments are all instrumental errors.

3. Personal error

Errors caused by limitations of the human sensory and motor organs. For some measurements that need to be judged by the human eye and the human ear, as well as measurement work that requires manual adjustment, human error will be introduced. For example: reading the wrong scale, reading the wrong reading, etc.

4. Use error

Also known as operation error, refers to the error caused by improper installation, adjustment, arrangement and use in the process of using the instrument. For example, the instrument that should be placed vertically according to the regulations is placed horizontally, the instrument is poorly grounded, the loss caused by the test lead is too long or the impedance matching is not considered, and the measurement is performed without preheating, adjustment, and correction according to the operating procedures.

5. Influence error

Also known as environmental error, refers to the additional error caused by the influence of temperature, humidity, air pressure, electromagnetic field, mechanical vibration, sound, light, radioactivity, etc.

From: Engineering Control Network