Final answer:
When measuring voltage with a digital multimeter, the leads should be connected in parallel with the circuit or the component being measured. This placement allows accurate measurement of the potential difference across that part of the circuit without disrupting the circuit's operation.
Step-by-step explanation:
When using a digital multimeter to measure the voltage in a circuit, the leads should be connected in parallel with the circuit. This means that one lead of the multimeter is connected to one side of the component or section of the circuit (for instance, across a resistor), and the other lead is connected to the other side. This parallel connection is important because it allows the multimeter to measure the potential difference or voltage across that specific part of the circuit without affecting the circuit's functionality. When measuring voltage, it's not necessary to connect the multimeter to the ground terminal unless you're specifically interested in measuring the voltage in reference to ground.
A common mistake is attempting to connect a voltmeter in series, which would not allow the correct measurement of voltage and could disrupt the circuit. Unlike ammeters, which are designed to measure current flow and are connected in series with the circuit element being measured, voltmeters must be connected in parallel to capture the voltage drop accurately across the device while maintaining the circuit intact.
If we were to summarize the process, place one lead of the multimeter at the positive terminal (point a) and the other lead at the negative terminal (point b) of the component or the voltage source to be measured. This method ensures that the voltage reading reflects the true voltage present at the points of interest.