| 摘要 |
A digital voltmeter for measuring the effective value of an alternating voltage comprises measuring and testing channels (1, 5) each of them consisting of the following elements connected in series: a commutator (2, 6), an alternating voltage amplifier (3, 7) and a converter (4, 8) of the effective value of the alternating voltage into the direct voltage, their outputs being connected to the inputs of an analog-digital computer (17). The output of the amplifier (7) of the alternating voltage of the testing channel (5) is connected, through the first voltage divider (9), to the first input of the commutator (2) the second input of which is connected to the first input of the commutator (6), whereas the second input of the commutator (6) is connected to the common bus. The output of the converter (4) is connected to the input of the second voltage divider (10) the second input of which is connected to the first input of an integrating amplifier (12) by means of the output of a switch (11) connected to the first input. The second input of the integrating amplifier (12) is connected to the output of the alternating voltage amplifier (7) whereas its output is connected to the commutating input of that amplifier (7). |
