How to measure power frequency with digital multimeter?
Some digital multimeters have frequency test gears. Simply set 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 or neutral line. By the way, insert the 220V power supply. On the socket, you can measure the power frequency.
The AC frequency of 50Hz was actually measured as 49.97. This result is relatively reliable. This is the operation method for measuring low-frequency frequencies.
For safety reasons, this method should not be used for measurement frequencies between phase line and phase line 380V to prevent damage to the input converter of the digital multimeter and personal safety.
If it is used to measure the detection frequency of induction cookers, you need to look at the frequency measurement range of the digital multimeter; the frequency measurement range of a cheap digital multimeter is narrow, the measurement accuracy is not high, and the error is relatively large. It can only be used as a preliminary judgment on the presence or absence of frequency. .
For example, the Udeli UT61 digital multimeter, which costs about 430 yuan, has a frequency measurement range of 10Hz ~ 10MHz and 10Hz ~ 220MHz. The measurement error is ±0.1%, and its 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 electrode (G) of the gate control tube (IGBT). The oscillation frequency can be measured and displayed. ;Generally, the working frequency of induction cooker IGBT is around 25~32KHz. It is strictly forbidden to connect the red test lead to the C pole of IGBT. When the DC voltage is 300V, the digital multimeter will be damaged.
The gears of the slightly more expensive digital multimeters are automatic, which is very convenient to use. Do not use a multimeter to measure high frequencies and high voltages that exceed the frequency measurement range. First, the measurement results are generally poor, and second, the digital multimeter is easily damaged.
