通过sparten2来实现数字电压表实验。实验板上的数码管显示模拟电压的数字，调整实验板上的控制模拟电压的电位器，显示模拟电压的数字应该能够随输入的电压变化而变化。-Sparten2 to achieve through the digital voltmeter experiment. Experiment on-board digital tube display the number of analog voltage to adjust the control experiment on-board analog voltage potentiometer, showing the number of analog voltage input voltage should be able to change with the change.