Measuring range of digital multimeter
⑴ AC and DC voltage (AC frequency is 45Hz ~ 500Hz); the measuring range is 200mV, 2V, 20V and 1000 respectively. The DC accuracy is ± (0.8% of the reading + 2 digits) or less, the AC accuracy is ± (the reading 1% + 5 words); input impedance, DC gear is 10MΩ, AC gear is 10MΩ, 100PF.
⑵AC and DC current
The measuring ranges are 200μA, 2mA, 200mA and 10A respectively. The DC accuracy is ±(1.2% of the reading + 2 digits), the AC accuracy is ±(2.0% of the reading + 5 digits), and the maximum voltage load is 250mV ( exchange effective value).
⑶Resistance:
The measuring ranges are: 200Ω, 2kΩ, 200kΩ, 20MΩ and 20MΩ. The accuracy is ±(2.0% of reading + 3 digits).
⑷Diode conduction voltage:
The measuring range is 0~1.5V, and the test current is 1mA±0.5 mA.
⑸ Transistor β value detection:
The test conditions are: VCE=2.8V, IB=10μA.
⑹Short circuit detection:
Test circuit resistance <20Ω±10Ω
Digital multimeter use
To measure AC and DC current, select the appropriate current measurement range and the insertion hole of the red test lead according to the size of the measured current. When measuring DC, the red test lead contacts the end with higher voltage, and the black test lead contacts the end with lower voltage. The forward current flows from the red test lead. The multimeter then flows out from the black test lead. When the magnitude of the current to be measured is unclear, first use the maximum range to measure, and then gradually reduce the range to measure.
