Electronic instrumentation refers to measuring instrument

Measuring instrument

In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item...

s used to measure the properties of electrical

Electronics

Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

devices.

Electronics Instrumentation is a subject which deals with various types of electrical instruments with their functionality and operation.

There are various Electrical\Electronics Instruments, broadly speaking they are analog instruments, digital instruments.
And even they are classified according to the utilization of voltage and current.

Measuring instruments are classified according to both
the quantity measured by the instrument as well the principle of operation.
Three general principles of operation are available:

(i)electromagnetic, which utilizes the magnetic effects of electric
currents

(ii) electrostatic, which utilizes the forces between electrically charged
conductors

(iii) electro-thermic, which utilizes the heating effect

{| class="wikitable sortable"
|-
! Type of Effect !! Type of Instrument utilizing the effect
|-
| Magnetic|| Ammeter, Voltmeter, Wattmeter
|-
| Electromagnetic Induction || AC Ammeter,DC ammeter