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Electronic Instruments
Electronic Instruments
 Those instruments which employ electronic
device for measuring various Electrical quantities
(eg. Volt , current , resistance etc ) is known as
electronic instruments .
There are large number of electronic instruments
available for completion for various test and
measurements .
voltmeter

A voltmeter is an instrument used for
measuring electrical potential difference between
two points in an electric circuit.
Oscilloscope

It display wave form signal.

An oscilloscope, previously called anoscillograph.

is a type of electronic test instrument that allows
observation of constantly “continuously over a
period of time; always. ”varying signal voltages,
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Oscilloscopes are used to observe the change
of an electrical signal over time, such that
voltage and time describe a shape which is
continuously graphed against a calibrated
scale.
Oscilloscope
ohmmeter
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An ohmmeter is an electrical instrument that
measures electrical resistance, the opposition
to an electric current.

Megaohmmeters measure large values of resistance.
The unit of measurement for resistance is ohms (Ω).

A more accurate type of ohmmeter has an electronic
circuit that passes a constant current (I) through the
resistance, and another circuit that measures the voltage
(V) across the resistance. According to the following
equation, derived from Ohm's Law, the value of the
resistance (R) is given by:
R=V/I
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What is the difference between
Analog and Digital Multimeter?

Analog multimeters give the output as a
reading on a scale against a pointer, while
digital multimeter output is in numerical
form displayed on a LCD.
Digital meter
Analog meter

Analog multimeters give a continuous output
and carry a greater uncertainty in the
measurement (about 3%), while digital
multimeter measurements have a far less
uncertainty (about 0.5% or less). Digital
multimeters are more accurate than analog
multimeters.

• Digital multimeters have a better range of
measurements than analog multimeters.

• Digital multimeters offer additional
features such as capacitance, temperature,
frequency, sound level measurements and
detection of semiconductor device pins
(transistor / diode)

Analog multimeters have to be calibrated
manually, while most digital multimeters are
calibrated automatically before every
measurement.

• Analog multimeters have to be set for the
specific range of measurement manually,
while some must digital multimeters have
auto ranging feature.

Analog multimeters require practice to take
good measurements, while digital
multimeters can be operated even by an
untrained person.

• Analog multimeters are less costly while
digital multimeters are expensive.