What Is a Voltmeter?
A voltmeter is a measuring instrument used to determine the voltage, or electrical potential difference, between two points in an electric circuit. Voltage is the 'pressure' from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop. The unit for voltage is the volt (V).
Section 2: How a Voltmeter is Used
To measure voltage, a voltmeter is connected in parallel to the component across which the voltage is being measured. This means the voltmeter's probes are placed on either side of the component. A key feature of a voltmeter is its very high internal resistance, which ensures it draws a negligible amount of current from the main circuit, thus providing an accurate measurement without significantly affecting the circuit's operation.
Section 3: A Practical Example
Imagine you want to check the voltage of a standard AA battery. You would set your multimeter to the DC voltage setting. Then, you would touch the voltmeter's red (positive) probe to the battery's positive terminal and the black (negative) probe to the negative terminal. The voltmeter's display would then show a reading, which for a new AA battery should be approximately 1.5 volts.
Section 4: Importance of Voltmeters
Voltmeters are fundamental tools for anyone working with electronics, from electricians to engineers and hobbyists. They are essential for diagnosing faults in circuits, verifying that power supplies are providing the correct output, and ensuring that individual components are receiving the appropriate voltage to function correctly and safely.