Which multimeter is better for professional electricians
The measurement error of the pointer multimeter is large and the conversion rate is slow, but the measurement of capacitor charge and discharge is intuitive, and the AC voltage block adopts half-wave rectification (diode rectification), so the measurement error of the pointer multimeter is large because the AC voltage block uses half-wave rectification, so it is said The AC voltage block of the pointer multimeter measures the average value of the alternating current. Because the measured AC signal is divided by the voltage dividing resistor and then rectified by half-wave rectification, it is rectified to be a direct current, which reflects the average value of the alternating current. The input impedance of the pointer multimeter does not have a digital multimeter. The input impedance is high, and the sensitivity is not as high as that of a digital multimeter, but professional electricians still recommend MF-47 pointer multimeter, the new MF-47 circuit design, the electric block and the current block are respectively equipped with varistors for overvoltage protection components, and some MF -47, MF-47 is not suitable for measuring AC for a long time, it is easy to cause the voltage divider resistance of the lowest gear of the AC voltage range and the rectifier diode in the rectifier to cause a large measurement error of the AC voltage range or failure of all gears of the AC voltage range, ( Burning out the lowest grade of the voltage dividing resistor in the series voltage dividing resistor in the AC voltage range, that is, the 38.3K resistor connected to the AC 10V range, will cause failure of all gears in the AC voltage range, and generally burn out the rectifier in the AC voltage range One of the two rectifier diodes in the AC voltage block will have a large measurement error or the failure of the AC voltage block) or that is, the gear switch is not in good contact, or the gear switch is short-circuited, causing the voltage divider resistor or the rectifier diode to burn Cause AC voltage block failure, because the current gear switches are all PCB switches.
Write down some of my experience in multimeter maintenance. It can measure alternating current, but it is not suitable for long-term measurement. The main purpose is to judge whether the 220V or 380V voltage is normal, but if the AC is measured frequently or for a long time, it will have an impact on the voltage dividing resistor and rectifier diode of the MF-47 AC voltage block. Prone faults have been written.
