HOW TO FIND ZERO ERROR AND LEAST COUNT OF VOLTMETER AND AMMETER?
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Least count for a measuring instrument means the smallest value that can be measured using the instrument. This can be calculated by dividing the maximum value that can be measured using the instrument by total number of divisions on the scale. Least count gives the resolution of the instrument.The above Voltmeter can measure up to 10 Voltsand has a total number of 25 divisions. Hence it’s least count is 10 V/25 divisions =0.4 V/division, meaning as least as 0.4 Volts can be measured using this voltmeter. Similarly for the shown ammeter least count can be calculated as 50 A/25 divisions=2A/division and hence as least as 2 Amperes can be measured using it.
Based on scale of operation, one can choose the meter with the appropriate Least count.
Ammeter or Voltmeter is said to have zero errorif their pointer doesn’t read zero when it is supposed to read i.e. when not connected to the circuit.
Before making connections, this zero error needs to be noted, if any. After connecting the meters to the circuit and upon measurement, this zero error needs to be accordingly added toor subtracted from the shown reading to get theactual reading.
Similar to least count, zero error is also applicable to other measurement devices.
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Based on scale of operation, one can choose the meter with the appropriate Least count.
Ammeter or Voltmeter is said to have zero errorif their pointer doesn’t read zero when it is supposed to read i.e. when not connected to the circuit.
Before making connections, this zero error needs to be noted, if any. After connecting the meters to the circuit and upon measurement, this zero error needs to be accordingly added toor subtracted from the shown reading to get theactual reading.
Similar to least count, zero error is also applicable to other measurement devices.
KEEP CALM
AND
SUPPORT
MATE'S
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⭕️First inspect the voltmeter/ammeter with no connection to it.
⭕️If the indicator hand is in the zero position then the zero error is 0. If it is showing 1 division then the zero error is 1 division.
⭕️It should be added to the voltage/ current measurement after connecting to circuit.
⭕️ This is called +ve zero error.
⭕️If the indicator hand is beyond the 0, then the zero error is called -ve zero error and the no.of divisions must be subtracted from the final reading.
⭕️Least count is the lowest possible measurement possible by a device.
⭕️ If a voltmeter has 10 small divisions make 1 volt then the least count will be 1/10 th of a volt.
⭕️ if 10 small divisions are shown 10 volt then the least count will be 1 volt.
⭕️If the indicator hand is in the zero position then the zero error is 0. If it is showing 1 division then the zero error is 1 division.
⭕️It should be added to the voltage/ current measurement after connecting to circuit.
⭕️ This is called +ve zero error.
⭕️If the indicator hand is beyond the 0, then the zero error is called -ve zero error and the no.of divisions must be subtracted from the final reading.
⭕️Least count is the lowest possible measurement possible by a device.
⭕️ If a voltmeter has 10 small divisions make 1 volt then the least count will be 1/10 th of a volt.
⭕️ if 10 small divisions are shown 10 volt then the least count will be 1 volt.
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