If the voltage measurement by the multimeter is in parallel and the measurement method is
Firstly, we can find a dry battery. As we all know, a No. 5 dry battery can provide a DC voltage of 1.5 volts. At this point, we only need to adjust the multimeter to the DC voltage of 2V, and then insert the red pin of the multimeter into the V Ω hole and the black pin into the COM hole. Connect the black pin to the negative terminal of the battery and the red pin to the positive terminal of the battery. The display screen should show a value of around 1.5V, which is the voltage of this dry battery.
As for the potential in the circuit board, we need to first estimate the size of the measured potential and choose a range larger than the estimated potential, such as 5V DC. We need to choose a range of 20V DC to avoid the measured potential being higher than the range and causing damage to the multimeter. Connect the black probe to the ground wire on the board. The ground wire can be found by checking the copper foil, which usually appears in pieces. Connect the negative electrode of the electrolytic capacitor used for filtering to the ground wire, then connect the red probe to the measured potential point and read the value. The difference between potential and voltage can be found in my article.
Measuring 220V AC power is somewhat dangerous, so we need to maintain a high level of concentration to avoid electric shock. As it is AC power, we need to adjust the gear of the multimeter to AC voltage 750V, then connect the red and black probes of the multimeter to the live and neutral wires respectively, and read the value.
