Does the multimeter measure voltage in parallel and how to measure it?
First, we can find a dry battery. We all know that a No. 5 dry battery can provide a DC voltage of 1.5 volts. At this time, we only need to adjust the multimeter to the DC voltage 2V range, and then turn on the multimeter. Insert the red test lead into the VΩ hole, insert the black test lead into the COM hole, connect the black test lead to the negative terminal of the battery, and the red test lead to the positive terminal of the battery. A value of about 1.5V should appear on the display. This is the voltage of this dry battery. .
As for the potential in the circuit board, we need to estimate the size of the potential to be measured first, and choose a range that is larger than the estimated potential. For example, if DC is 5V, we need to choose a range of DC 20V to avoid the measured potential being higher than the range and causing the multimeter to malfunction. damage. Connect the black test lead to the ground wire on the board. You can find the ground wire by looking at the copper foil. Usually the copper foil appears in pieces, and connect it to the negative electrode of the electrolytic capacitor for filtering. Find the ground wire, and then connect the red test lead to the ground wire. Measure the potential point and read the value. (The difference between potential and voltage can be found in my article).
Measuring 220V AC is a bit dangerous, so we need to stay highly focused to avoid electric shock. Since it is alternating current, we need to adjust the multimeter's gear to the AC voltage 750V gear, and then use the red and black test leads of the multimeter to connect the live and neutral wires respectively, and read the values.
How to use a digital multimeter to test the mainboard of a gas water heater
Gas ignition generally consists of two battery-powered DC igniters. It is rarely bad, the situation is that there is no arcing (sparks) on the iron tip. The reason is that it is rusty and does not conduct electricity. Take it out and touch it with sandpaper a few times. Or replace it with a copper wire that is more resistant to burning. Because when the burner is used to heat hot water, the burner is always burning, and it will rust over time. The output voltage is 5 to 9v, set the multimeter to DC, the line of the flamethrower is the positive pole, and the "S" shaped elbow inside is the negative pole. You can also use a black test pen and a red pen from the negative electrode of the battery to connect the ignition line (the line that sprays sparks). In some cases, the tube inside is oxidized and rusted, which also results in no sparks. (Because it's the negative pole). The above tests are normal, but the problem is that the water pressure is too low.
Testing with a multimeter is an ordinary testing tool. Not all faults of the It is difficult to maintain the above points, and it cannot be known by just setting up a multimeter.
