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一般的交流电压表,最多能精确地测量频率到200Hz的交流电压,而本表能测量高达100KHz的各种波形的交流电压,这主要是借助了几种集成电路的应用。图1是用100倍反相放大器和普通万用表25V档配合进行直流电压测量的原理电路,由于是反相放大器,故表的正端接地,而负端接到运放的输出端。要测量交流电压,一般采用有效值电压表,首先将交流电压整流为直流电压,再在刻度为有效值的直流电压表上读出数值。常采用图2那样的二极管整流电路,但由于二极管具有0.6~0.7V的正向压降,故低于
The general AC voltmeter, up to accurately measure the frequency of AC voltage to 200Hz, and the table can measure up to 100KHz AC voltage of various waveforms, mainly through the use of several integrated circuit applications. Figure 1 is 100 times the inverting amplifier and ordinary multimeter 25V file with the principle of DC voltage measurement circuit, because it is an inverting amplifier, so the positive end of the table grounded, and the negative terminal connected to the op amp’s output. To measure the AC voltage, the general use of RMS voltmeter, the first AC voltage rectifier DC voltage, and then read out the value of the scale of the RMS voltmeter. Diode rectifier circuit as shown in Figure 2 is often used, but because the diode has a forward voltage drop of 0.6 ~ 0.7V, it is lower than