How To Use Electrical Measuring Instruments To Measure Functions (Voltage, Current, Resistor)

Testing Battery Voltage

This post is about how to use the various measuring instruments to measure current, voltage and resistance. We have two types of meters, that is analogue meter and digital meter. The he analogue meter movement uses a pointer or a scale and is one of the most common meter used for electrical and electronic measurements. This meter is available as an individual that is amps, volt and ohms or that is combining or three functions.

Voltage measurement- Voltmeter

A vote meter measures the potential difference between two points in a circuit for example between the terminals of a battery or resistor. Voltmeters are always connected in parallel across the test load.

The general rules for the measurement of voltage are

• Select the voltage function either AC or DC as appropriate
• Select the highest voltage range
• Connect the meter across the component or circuit being measured. For or DC measurement, the red lead is connected to the positive point, the black lead is connected to the negative point
• Record the Reading on the voltage scale on the meter
• Change to a lower scale if necessary

For all voltmeter connections, always consider polarity for DC voltage only

Current measurement - Ammeter

Current flow within a circuit is measured with an instrument called an ammeter. To effectively measure the current flowing within a conductor with an amateur it is necessary to cut the conductor and insert the ammeter between the ends in order that, the current passes through the ammeter

The general rules for the measurement of current are

• Remove the power to the component or circuit being measured
• Select the current function either AC or DC as required
• Select the highest current range
• Break the circuit at the test point to measure the current
• Connect the metet in series with the component or circuit being measured with DC measurement ensure that the most positive point is connected to the red lead and the black lead is connected to the negative point
• Re apply power to the test circuit
• Record the Reading from the current scale on the meter
• If current readings appear low change to a lower scale to show a more easily read value

Resistance measurement - Ohmmeter

Resistance values are measured with an instrument called an ammeter when resistance is measured the m requires an internal battery the resistance being measured be disconnected from supply power and other visitors failure to do both actions may result in meter damage

The general rules for the measurement of resistance are

• Remove the power to the circuit being measured
• Select the ohms function
• Select the appropriate ohms range
• At the meter connect the red and black leads and adjust the meter to read zero ohms
• Disconnect the component from the circuit
• Connect the meter leads across the component or circuit being measured
• Record the Reading on the ohms scale on the meter
• Change the scale if required to obtain an accurate Reading from the non linear scale

It is very interesting to use the testing and measuring devices. All safety precautions must put in place when working with system with connected power source.