Give specific instructions on how to measure voltage with a multimeter.
The measurement process of the digital multimeter converts the measured value into a DC voltage signal by the conversion circuit, and then converts the voltage analog quantity into a digital quantity by the analog/digital (A/D) converter, then counts through the electronic counter, and finally uses the digital measurement result displayed directly on the display.
The function of the multimeter to measure voltage, current and resistance is realized through the conversion circuit part, while the measurement of current and resistance is based on the measurement of voltage, that is to say, the digital multimeter is expanded on the basis of the digital DC voltmeter.
The A/D converter of the digital DC voltmeter converts the analog voltage quantity that changes continuously with time into a digital quantity, and then the digital quantity is counted by the electronic counter to obtain the measurement result, and then the measurement result is displayed by the decoding display circuit. The logic control circuit controls the coordinated work of the circuit, and completes the entire measurement process in sequence under the action of the clock.
How to measure voltage with a multimeter
1. The multimeter is our commonly used test tool
It is mainly used to test parameters such as voltage, resistance, and current, and plays a great role in the testing, maintenance and production of electronic products. The main components of a multimeter are an ammeter, a dial, a range selection switch, and test leads. There are many models of multimeters, but basically the method of use is the same. Let's introduce the method of using a multimeter to measure the power supply and the principle of the multimeter to measure the voltage.
2. Multimeter voltage measurement method
The method of measuring voltage with a multimeter firstly aligns the range switch within the range of the fifth gear marked with V (when testing AC voltage, align it with the gear of AC voltage, and when testing DC voltage, align it with the gear of DC voltage). When measuring the voltage, the ammeter pen should be connected to the circuit under test. According to the approximate value of the circuit under test, select an appropriate range position. The maximum value of each dry battery is 1.5V, so it can be placed in the 5V range. At this time, the 500 of the full scale reading of the hands on the panel should be read as 5. i.e. scaled down by a factor of 100. If the needle is at the 300 mark, it reads 3V. Note that the value indexed by the tip of the range switch is the corresponding value of the full-scale reading of the needle on the meter head. When reading the meter, you only need to convert it accordingly to read the real value. Except for the resistance range, all range switch ranges can read the measurement results in this way. In the actual measurement, when the approximate value of the measured voltage cannot be determined, the switch can be turned to the maximum range first, and then the range can be reduced step by step to a suitable position. Pay attention to the positive and negative polarity when measuring DC voltage. If the test leads are reversed, the test needles will reverse. If you do not know the positive and negative polarity of the circuit, you can put the range of the multimeter on the maximum range, try it quickly on the circuit under test, and see how the pen needle deflects, you can judge the positive and negative polarity
3. Measure 220V AC
Turn the range switch to AC 500V. At this time, the full scale is 500V, and the reading is read according to the scale 1:1. Insert the two test leads into the power socket, and the measured voltage value is at the scale where the hands point to. When measuring AC voltage, there is no difference between positive and negative test leads.
