A pointer multimeter is a magnetoelectric instrument that is the most commonly used in electrical and electronic measurements. Among pointer multimeters, the MF500 type multimeter has become the preferred choice due to its high sensitivity. The MF500 multimeter can measure DC voltage, DC current, intermediate frequency AC voltage, audio level, and resistance. Due to the extremely small amount of current consumed during measurement, the impact on the circuit parameters with high internal resistance is minimal, making it a common instrument for electronic measurement work. The measurement range of MF500 is as follows: (a) DC current: 0-500mA, divided into six levels. (b) DC voltage: 0-500V, divided into six levels, specifically for 2500V level. (c) AC voltage: 0-500V, divided into six levels, specifically for 2500V level. (d) Resistance: 0-20M, divided into six gears. (e) Audio level: -10-+50dB. The accuracy level of the MF500 multimeter is as follows: (a) DC current and voltage: 2.5 (expressed as a percentage of the upper limit of the working part of the scale). (b) AC voltage: 5.0 (expressed as a percentage of the limit on the working part of the scale). (c) Resistance: 2.5 (expressed as a percentage of the length of the working part of the scale). The appearance of the MF500 pointer multimeter is shown in Figure 2-1. Before use, it is necessary to adjust the zero adjuster "S3" to accurately indicate the pointer at the fully scaled zero position. The MF500 multimeter can perform the following measurements. (1) For DC voltage measurement, insert the short rod of the test rod into K1 and K2 respectively, rotate the transfer switch knob S1 to the "~V" position, rotate the transfer switch knob S2 to the corresponding range position of the DC voltage to be measured, and then connect the long rod of the test rod across both ends of the circuit to be measured. When the measured DC voltage value cannot be estimated, rotate the switch knob to the maximum range position, and select an appropriate range position based on the indicated value, Maximize the deflection of the pointer. When measuring the voltage of 2500V, insert the short pole of the test rod into the K1 and K4 sockets. (2) For AC voltage measurement, turn the switch knob to the "~V" position, and turn the switch knob S2 to the corresponding range position of the AC voltage value to be measured. The measurement method is the same as for DC voltage measurement. The indicated values for ranges of 50V and above are shown on the "" scale, and the 10V limit is shown on the "10V" dedicated scale. (3) For DC current measurement, turn the switch knob S2 to the "A" position, and turn the switch knob S1 to the corresponding range position where the DC current value needs to be measured. Then, connect the test rod to the circuit under test to measure the DC current value in the circuit under test. The indicated value is indicated by the " " scale. (4) Resistor measurement Turn the switch knob S2 to the "Ω" position and the switch S1 to the "Ω" range. First, short circuit the two test poles to deflect the pointer to the full scale, and then adjust the potentiometer R1 so that the pointer is at the "0 Ω" position of the ohmic scale (when the potentiometer R1 cannot be adjusted so that the pointer shows the ohmic zero position, it means that the battery voltage is insufficient and the battery should be replaced). Separate the test markers again to measure the resistance value of the unknown resistor. The indicated value is shown on the "Ω" scale. Author: Tomato Flavored Monster https://www.bilibili.com/read/cv16579164/ Source: Bilibili