Principle of digital multimeter: high sensitivity magneto-electric DC current correction (microammeter) as the head use. When a small current passes through the collector, there is a current display. However, because the collector cannot flow through large current, it must be shunt or step-down in parallel with several resistors connected in series on the collector to measure the current, voltage and resistance in the circuit.
Digital multimeter features: strong resolution, high accuracy (±0.5%~±0.03%), complete test function, fast measurement speed, visual display, energy consumption, power saving, overload ability is strong, easy to carry. Trends: Automatic range, chart display, "digital/analog bar graph". The dual display digital multimeter overcomes the disadvantage of not being able to reflect continuous changes in measurement. Features of a digital multimeter :31/2 digits): The first digit can display only 0 or 1, and the other digits can display only 0 to 9. The base range is 200mV, with a header Z large display value of 199.9.
After the DC voltage is entered into the digital multimeter, use cl to separate the input and output of the IC2b. Because of the pull-up resistance inside the Icl, FC1=l(high level), the multimeter automatically enters DC voltage measurement mode.
Because the pure system of digital multimeter is controlled by electric signal, the conversion process of AC/DC measurement function is fast, no manual operation, very convenient.