When testing, we must first find the testing source. Because we are qualitative and quantitative measurement, there are many testing sources available. The household testing sources include 1.5V alkaline/carbon batteries (No. 1, No. 5/AA, 7 No./AAA), 1.2V rechargeable battery, mobile phone charger, power adapter, etc.
When testing, turn the digital multimeter to the required DC voltage range, insert the test leads according to the instructions, connect the testing source, and read the reading on the LCD, as long as the measured value is around the nominal voltage. .
