How to use a digital multimeter to measure power frequency?
Some digital multimeters have a frequency testing gear. Simply set the gear to the frequency Hz position, insert the red probe into the V/Ω/Hz hole, and the black probe into the com hole. The two probes do not recognize the phase and zero lines, and can be inserted into a 220V power socket to measure the power frequency.
The actual measurement of 50Hz AC frequency is 49.97, which is relatively reliable. This is the operating method for measuring low-frequency frequencies.
For safety reasons, this method should not be used for measuring frequencies between phase lines of 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 cooking, you need to look at the frequency measurement range of the digital multimeter; The frequency measurement range of cheap digital multimeter is narrow, the measurement accuracy is not high, and the error is relatively large, which can only be used as a preliminary judgment of the presence or absence of frequency.
For example, the Youdeli UT61 digital multimeter, priced at around 430 yuan, has a frequency measurement range of 10Hz~10MHz and 10Hz~220MHz, with a measurement error of ± 0.1%. Its measured frequency is relatively accurate.
The method of measuring frequency with this digital multimeter is simple, and there is a common ground in the electronic circuit, commonly known as GND; Connect the black lead of the multimeter to GND and the red lead to the control electrode (G) of the gate control transistor (IGBT) to measure and display the oscillation frequency; Generally, the working frequency of the IGBT of the Induction cooking is about 25~32KHz. It is forbidden to connect the red probe to the C-pole of the IGBT. When the DC voltage is 300V, the digital multimeter will be damaged.
The gears of slightly more expensive digital multimeters are automatically shifted, making them very convenient to use. Do not use a multimeter to measure high-frequency and high voltage beyond the frequency measurement range. Firstly, the measurement results are generally poor, and secondly, it is easy to cause damage to the digital multimeter.
