Detailed analysis of pointer type multimeter use and precautions

(1) Usage method and precautions for pointer type multimeter (1) Mechanical zero adjustment: First check whether the pointer is at zero before use. If it is not at zero, adjust the zero adjuster to adjust the pointer to zero. .
(2) Connect the test leads correctly: The red test lead should be inserted into the jack marked "+", and the black test lead should be inserted into the "-" jack. When measuring DC current and DC voltage, the red test lead is connected to the positive pole of the measured voltage and current, and the black test lead is connected to the negative pole. When using the ohmic "Ω" to judge the polarity of the diode, note that the "+" jack is the negative terminal of the battery inside the watch, and the "-" jack is the positive terminal of the battery inside the watch.
(3) When measuring voltage, the multimeter should be connected in parallel with the circuit under test; when measuring current, disconnect the circuit under test and connect the multimeter in series to the circuit under test. Note: When measuring current, estimate the current to be measured. Select the correct range. The fuse of MF500 type is 0.3A~0.5A, and the measured current cannot exceed this value. Some multimeters have a 10A gear that can be used to measure large currents.
(4) Range conversion: power should be cut off first, and the range should not be allowed to be charged; if the measurement is placed in the correct position, the current or ohms should not be used to measure the voltage, otherwise the multimeter will be damaged.
(5) Reasonable selection of range block: When measuring voltage and current, the hand should be deflected to 1/2 or 2/3 of the full scale; when measuring the resistance, the hand should be deflected to the vicinity of the center mark (the design of the electric barrier is The center scale is standard). When measuring AC voltage and current, be careful that the measured voltage must be sinusoidal AC voltage and current, and the frequency of the measured signal should not exceed the specifications in the manual. When measuring the AC voltage below 10V, the reading should be marked with a special scale of 10V, and its scale is not equidistant.