How to select a automobile digital multimeter?
In order to meet the needs of the measurement of the various functional parameters of the car, In addition to voltage, resistance, current, diode performance, circuit on-off (using buzzer block), automatic shutdown, low voltage display, over-range (overload) display, automatic display type of measurement, the selected digital multimeter is required to have voltage, resistance, current, diode performance, circuit on-off (using buzzer block), automatic shutdown, low voltage display, In addition to functions such as auto-display polarity, Also has the engine speed, the breaker contact close angle, the frequency, the duty cycle, the temperature, the pressure and so on detection function.
2. Select specific requirements for each functional block.
The specific requirements for each function block of the selected digital multimeter are shown in Table 3-2 for reference when selecting the appropriate digital multimeter.
Table 1 Specifies the specific requirements for each functional block of the digital multimeter selected for the vehicle.
Specific request description
Choose the car digital multimeter to be able to measure the resistance around the 2MΩ and the measurement range is as large as possible.
Choose a car digital multimeter to be able to measure current greater than 10A and measure as much as possible.
Ac and DC voltage measurement
The selected automobile digital multimeter should be able to measure voltages greater than 48V, but the measurement range should be controlled not to be too large in case the measurement accuracy is reduced.
Measurement of rotational speed and output pulse signal.
The selected automobile digital multimeter should have the function of measuring rotational speed and output pulse signal in order to conveniently measure the fault of ignition system without distributor.
Duty cycle, closure angle measurement
The selected digital multimeter should have the function of duty cycle (frequency-width ratio) and close angle measurement, which is convenient to measure the duty cycle of pulse waveform and the closing angle of primary current of ignition coil.
Maximum value, minimum value memory
Choose the automobile digital multimeter to have the maximum value, the minimum value memory function, uses to carry on the inspection to the circuit instantaneous bad fault.
Analog bar display function.
The car digital multimeter selected should have the analog bar display function for observing data of continuous changes.
The automobile digital multimeter selected shall have the function of temperature measurement so that the cooling water temperature, intake air temperature, automobile exhaust temperature and so on can be measured in conjunction with the temperature sensor.
The selected automobile digital multimeter shall have a frequency measurement function to facilitate the measurement of the frequency of the output signals of various sensors.
The selected automobile digital multimeter should have extended pressure measurement functions (e.g., EDA- 230 automobile digital multimeter, etc.) to facilitate the measurement of air pressure, vacuum, etc., in conjunction with vacuum / pressure converters.
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