Analog Instruments

The analog instrument is a device whose output is a continuous function of time. these types of instruments usually use pointers for the indication. for ex. ammeter, voltmeter, wattmeter, etc.

Classification of Analog Instruments

The classification of the analog quantity depends on the number of the physical quantity they measures. For example, the instrument uses for measuring the current is known as the ammeter and the voltmeter is used for measuring the voltages. The wattmeter and the frequency meter measures the power and frequency respectively. The analog instrument is classified by the type of current that can be measured. The following are the types of an electrical instrument.

1. Direct Current Analog Instruments
2. Alternating Current Analog instrument
3. Both Direct and Alternating current Instruments.

The analog instruments can also be classified by showing the output of the measured quantity. The different type of analog instruments are shown below

• Indicating
• Recording
• Integrating Instruments

Indicating Instrument – The indicating instruments indicate the instantaneous magnitude of the measured quantity. The ammeter and voltmeter belong to this category. The integrating instruments are of two types. They are

• Electromechanical Instruments
• Electronic Instruments

Recording Instrument – Such type of instruments gives a continuous reading over a specified period. The variations in quantities are recorded on the sheet of papers. ECG is giving the record of heart rate, and a recording voltmeter is used in the sub-station to analyze the variation in voltage all over the day.

Integrating Instruments – The instrument which measures the summation of the electrical quantity over a given period is known as the integrating instruments. Ampere-hour and watt-hour meters are examples of this category.

The classification of the analog instruments can also be done by the methods used by the instruments for comparing the measured quantity. The following are the classifications of the instrument by the methods.

1. Direct measuring Instruments – The instruments directly convert the measurand into energy which activates the instruments and the value of the unknown quantities measured through it. Ammeter, Voltmeter, Wattmeter, and the energy meter are examples of the direct measuring instruments.

2. Comparison Instruments – The comparison instruments measure the unknown quantity by comparing it with the standard value. The example of the comparison instruments is the ac and dc bridges.