Which Multimeter Range to Use for Voltage Measurement; How to Measure Current with a Multimeter
A multimeter is an electronic testing instrument used to measure voltage, current, and resistance. It is a commonly used tool for electricians, electronic engineers, and those who have a need for current and voltage. When using a multimeter to measure voltage, it is necessary to select the appropriate range gear; When measuring current, it is necessary to pay attention to the safety of the instrument and choose the appropriate current measurement gear.
Before using a multimeter to measure voltage, it is necessary to first select the appropriate range gear. In general, we can choose the minimum range gear slightly larger than the measured value. The minimum range gear can measure voltage values more accurately, while a larger range gear can avoid instrument burnout caused by excessive measurement values.
Next, connect two test pens to the two ends of the voltage to be tested. Generally, the red test pen is used to connect the positive pole, and the black test pen is used to connect the negative pole. In this way, the display screen of the multimeter will show the value of the voltage to be measured.
It should be noted that a multimeter generally has two measurement ranges: DC voltage and AC voltage. Before measuring voltage, it is necessary to select the type of voltage to be measured by selecting the knob on the instrument. If not otherwise specified, the DC voltage measurement range can be selected by default.
When measuring current, there may be additional difficulties and safety hazards. Since current measurement is achieved by inserting resistors into the circuit and measuring the voltage across the resistors, it is necessary to ensure that the resistors in the circuit can stably pass current.
Before measuring the current, it is necessary to first disconnect the circuit and then select the appropriate current gear. When selecting the current gear, it is important to pay attention to the current measurement range and choose the minimum range gear that is slightly larger than the current being measured.
Next, insert the test pen for measuring current into the appropriate socket on the instrument. Note that when measuring current, the red test pen should be inserted into the socket marked as "mA" or "A" on the instrument, while the black test pen should be inserted into the socket marked as "COM". In this way, the multimeter can start measuring the current.
When measuring current, it is necessary to connect the two test pens of the instrument to two nodes in the circuit under test. In general, the red test pen is connected to the point of current inflow, while the black test pen is connected to the point of current outflow.
It should be noted that when measuring current, the load resistance in the circuit will introduce uncertainty. Therefore, in order to reduce measurement errors, a smaller load resistance can be chosen or a specialized current measurement resistor can be used.
During the operation, it is necessary to always pay attention to the safety of the multimeter. When inserting and removing the test pen for measuring current, it is necessary to ensure that the circuit is in a disconnected state to avoid the risk of electric shock caused by excessive current.
The above are the basic steps for measuring voltage and current using a multimeter. In practical operation, the appropriate range gear should be selected according to the specific situation, and relevant electrical safety regulations should be followed.
