Electric voltage, also known as electrical potential difference, is the measure of the potential energy difference between two points in an electrical circuit. It is typically measured using a device called a voltmeter. There are various types of voltmeters, but the most common one is the digital multimeter (DMM). Here's a general procedure for measuring electric voltage using a DMM:
Note: When working with electricity, always exercise caution and follow safety guidelines to prevent electric shocks or other hazards.
Materials needed:
Digital Multimeter (DMM) - capable of measuring voltage (AC and/or DC).
Test leads (usually red and black) with probes at the ends.
Steps:
Prepare the Circuit: Ensure that the circuit you are measuring is disconnected from any power source. If you are measuring voltage in a live circuit, exercise extreme caution, and make sure you are familiar with electrical safety procedures.
Set the DMM to Voltage Mode: Turn on your digital multimeter and set it to measure voltage. Usually, there are different settings for AC voltage (V~) and DC voltage (V=). Select the appropriate mode depending on the type of voltage you want to measure.
Check the Range: Look at the range selector on the DMM. Choose the voltage range that is higher than the expected voltage. For example, if you expect the voltage to be around 5 volts, select a range higher than 5 volts, such as 20 volts or 50 volts.
Insert the Test Leads: Connect the test leads to the DMM. Most DMMs have two input jacks labeled "COM" (common) and "VΩmA" (for voltage, resistance, and current). Insert the black test lead into the COM jack and the red test lead into the VΩmA jack.
Connect the Test Leads to the Circuit: Touch the metal probe tips of the test leads to the two points between which you want to measure the voltage. Connect the red probe to the point with higher potential (positive) and the black probe to the point with lower potential (negative).
Read the Display: Once the test leads are connected, the DMM should display the voltage reading on its screen. If you're using an auto-ranging DMM, it will automatically select the appropriate range and display the value. If you're using a manual-ranging DMM, ensure that you're reading the correct scale on the display.
Polarity: Take note of the polarity of the voltage, which indicates the direction of the potential difference between the two points. A positive voltage reading indicates that the red probe is at a higher potential than the black probe, while a negative reading indicates the opposite.
Disconnect and Power Off: After taking the measurement, disconnect the test leads from the circuit and power off the DMM to preserve its battery life.
Remember, voltage measurements should always be done carefully, especially in live circuits, to avoid accidents and injuries. If you are unsure or inexperienced, it is best to seek the help of a qualified electrician or someone with expertise in electrical measurements.