How to use a digital multimeter to measure the power frequency?
Some digital multimeters have a frequency test gear, directly dial the gear to the frequency Hz position, insert the red test lead into the V/Ω/Hz hole, and the black test lead into the com hole, the two test leads do not recognize the phase line and neutral line, and insert the 220V power supply by the way Plug in the socket to measure the frequency of the power supply.
The measurement frequency shows the AC frequency of 50Hz, and the actual measurement is 49.97. This result is relatively reliable. This is the operation method for measuring low frequency frequency.
For the sake of safety, this method is not suitable for measuring the frequency between the phase line and the phase line 380V, in order to prevent damage to the input converter of the digital multimeter and personal safety.
If it is used to measure the detection frequency of an induction cooker, you need to look at the frequency measurement range of the digital multimeter; the frequency measurement range of the cheap digital multimeter is narrow, the measurement accuracy is not high, and the error is relatively large, so it can only be used as a preliminary judgment of the frequency. .
Digital multimeter, the price is about 430 yuan, the frequency measurement range is 10Hz~10MHz and 10Hz~220MHz, the measurement error is ±0.1%, and the measured frequency is relatively accurate.
The method of measuring frequency with this digital multimeter is simple. There is a common ground in the electronic circuit, commonly known as GND; connect the black test lead of the multimeter to GND, and the red test lead to the control pole (G) of the gate control tube (IGBT), and the oscillation frequency can be measured and displayed. ;Generally, the working frequency of the IGBT of the induction cooker is around 25~32KHz. It is strictly forbidden to connect the red test lead to the C pole of the IGBT. When the DC voltage is 300V, the digital multimeter will be damaged.
The gears of the slightly more expensive digital multimeters are automatically shifted, which is very convenient to use. Do not use a multimeter to measure high frequency and high voltage exceeding the frequency measurement range. First, the measurement results are generally poor, and second, it is easy to cause damage to the digital multimeter.
