Proper Operating Procedures for Analog Multimeter
Select the measurement function and range switch on the multimeter according to the measured quantity. If the order of magnitude of the measured value is known, choose the corresponding range. If the order of magnitude is unknown, start measurement with the maximum range. Reduce the range only when the pointer deflection angle is too small for accurate reading.
How to Use an Analog Multimeter
① Before measurement, place the multimeter horizontally and check whether the pointer rests at the zero position for current‑voltage scales. If not, adjust the mechanical zero‑adjustment screw below the meter movement to align the pointer with zero.
② Select the correct measurement function and range switch according to the measured quantity. If the order of magnitude of the measured value is known, select the matching range. If the order of magnitude is unknown, start with the maximum range. Decrease the range if the pointer deflection angle is too small for precise reading. A reasonable range shall ensure the pointer deflection is no less than 30 % of the full‑scale value.
Using the Multimeter as an Ammeter
① When connecting the multimeter in series to the test circuit, pay attention to current direction. Connect the red test‑lead to the current‑inflow terminal and the black test‑lead to the current‑outflow terminal. If the current direction is unknown, fix one test‑lead to one circuit terminal and briefly touch the other test‑lead to the opposite terminal. Right‑hand pointer deflection indicates correct connection. Left‑hand deflection (below zero scale) means reversed polarity; swap the two test‑leads.
② When the pointer deflection reaches 30 % or more of full scale, prefer a higher range. Larger ranges feature smaller shunt resistance and lower equivalent internal resistance of the ammeter, which brings less interference error to the measured circuit.
③ When measuring large current (e.g. 500 mA), never turn the range selector during measurement. Arcing may occur and burn the contacts of the range‑switch.
