| 摘要 |
This invention is to provide a driving apparatus and a method for a digital multimeter that contains functions of a wattmeter and a multi-display. According to the invention, the present multimeter comprising: an adapter provided with two input terminals (A, B) connected to a power supply, connecting parts (F, G) to be connected with a load which is in need to measure and three output terminals (C, D, E) which will be respectively inserted to outside terminals (X, Y, Z) of the present digital multimeter; a common terminal part (22) connected with the input terminal (Y) and output terminal (D) of the adapter so to ground thereof; a voltage attenuation driving part (21) to attenuate input voltage from the input terminal (X) which is connected with the output terminal (C) of the adapter; an A/D converting part (24) that converts input AC voltage from the voltage attenuation driving part (21) to DC voltage; and A/D converting part (31) to digitalize the analog DC voltage output from the A/D converting part (24); an amplifying part (26) for amplifying the AC voltage output from the voltage attenuation driving part (21); a current-voltage converting part (23) which may convert current inputted from the input terminal (Z) which is connected with the output terminal (E) of the adapter to voltage within the limit of 20A against voltage; an AC-DC converting part (25) that converts the AC current waveform output from the current-voltage converting part (23) to RMS direct current; an A/D converting part (28) to digitalize the analog voltage output from the A/D converting part (25); an amplifying part (27) to amplify the AC signal output from the current-voltage converting part (23); a microprocessor (29) to control the measurement of power factor on the basis of the respective measured factors; and a display driving part (30) that shows respective measured values simultaneously under the control of the microprocessor (29).
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