What are the reasons for inaccurate display of digital ammeter?
1. Circuit parameter factors
(1) Influence of circuit load impedance
In a circuit, the equivalent impedance of the load is an important factor affecting the measured value of the ammeter. If the impedance of the ammeter itself does not match that of the load, it will cause a reading deviation of the ammeter. For example, when the current measured by the ammeter passes through a load with impedance close to infinity, the ammeter only displays the no-load voltage value in the circuit.
(2) The influence of line resistance
The resistance value of the circuit may also affect the accuracy of the ammeter reading. When the line resistance is high, the current passing through the line resistance of the tested circuit will cause a voltage drop, resulting in a large deviation in the ammeter reading.
2. Factors related to the ammeter itself
(1) Accuracy level
The accuracy level of an ammeter refers to the maximum error range that the ammeter can achieve. If the accuracy level of the ammeter used is low, the reading error will increase. Therefore, choosing the appropriate accuracy level of the ammeter is one of the important factors to ensure accurate readings.
(2) Bandwidth
The bandwidth of an ammeter refers to the measurement frequency range. If the frequency of the tested circuit deviates from the bandwidth of the ammeter, it will also cause a deviation in the current value displayed on the ammeter.
(3) Power supply voltage
The unstable power supply voltage of the ammeter may also affect the accuracy of the reading. The power supply used for measuring the ammeter should be a stable DC power supply or a calibration source.
3. Operational factors
(1) Measurement method
The reading error of the ammeter may also be related to the measurement method. If the ammeter does not match the measured circuit or the measurement method is incorrect, the displayed value of the ammeter may not match the actual measured value. Therefore, when choosing a measurement method, it should be based on the actual situation.
(2) Environmental factors
Measuring environmental factors may also affect the accuracy of ammeter readings. For example, the influence of electromagnetic fields, high temperatures, high humidity, etc. can all cause deviations in the current values displayed on the ammeter.
