There are a number of test instruments for measuring electrical quantities. Of all the test instruments the most used is the multimeter because of its flexibility and relatively low cost. This post is to help you learn how to measure voltage current and resistance.
In electronics the color black is used for negative and red stands for positive. Plug the black test lead into the common jack and the red test lead into the V/W/mA jack.
Measuring Voltage
The procedure for measuring voltage is as follows:
Set the function switch to the appropriate function (AC or DC voltage) and the highest range.
Since voltage is the difference of potential between two points, voltage is always measured across a resistance or voltage to be measured (as shown).
Then reduce the voltage range to obtain the best reading. To measure voltage, the meter is always connected in Parallel with the
voltage you are measuring.
Measuring Current
The procedure for measuring current is as follows:
Set the function switch to the appropriate function (DC current) and the highest mA range for low current measurement or 10A range for high current measurement (For the 10A range you must move the red test lead to the 10A jack).
Current is charge in motion through the circuit. To measure it, you must break its path and insert the meter in series. Current is always measured in series allowing the current in question to pass through the meter (as shown).
Then adjust the current range to obtain the best reading.
Measuring Resistance
The procedure for measuring resistance is as follows:
Set the function switch to the appropriate function (W).
Disconnect all voltage sources from the circuit, device, or component whose resistance you want to measure.
Place the meter probes in parallel with the circuit, device, or component as shown.
Set the range to obtain the best reading.