How to measure the Current, Voltage and Resistance How to measure the current The instrument used to measure current is called ampere meter or ammeter. Example of Current Measurement, Connect a small light bulb to a dry cell. Measure the current that pass through the light bulb by connecting the positive terminal (+) of ammeter to the negative terminal (-) of a dry cell (see picture). Safety information for current measurement Estimate the current that required measuring then choose a suitable ammeter, as each ammeter has different limit of current measurement Be sure that the connection to the positive terminal (+) and the negative terminal (-) of ammeter are correct Do not directly connect the ammeter terminals to the dry cell terminals. Since it can damage the meter. How to measure the voltage The instrument used to measure the voltage, difference potential or electromotive force is called voltmeter. Example of Voltage Measurement, Connect a small light bulb to a dry cell. A voltmeter is wired in parallel with the light bulb to measure the voltage across the light bulb. Connect the positive terminal (+) of voltmeter to the positive terminal (+) of a dry cell and connect the negative terminal (-) of voltmeter to the negative terminal (-) of a dry cell (see picture). Safety information for measuring voltage: Estimate the voltage that required measuring then choose a suitable voltmeter, as each voltmeter is designed with the limit of voltage measurement Be sure the connecting of the positive terminal (+) and the negative terminal (-) of voltmeter are correct How to measure the resistance The instrument used to measure the resistance is called test meter or multimeter. The multimeter or test meter is used to make various electrical measurements such as current, voltage and resistance. It combines the functions of ammeter, voltmeter and ohmmeter. Example of Resistance Measurement, Turn the face dial to a position for the required measuring, resistance, then touch both of terminals of multimeter (see picture 1) and adjust the meter range to 0 Ω. Touch both of terminals of meter to a resistance and take the reading (see picture 2).