Fig. 1: Image of a Digital Panel Voltmeter
With a single IC L 7107, you can make a 4 digit voltmeter that can show 0-2000 voltsthrough seven segment display. The circuit is low component one and the reading is reliable and accurate. This circuit is used in digital panel meters to give alpha numerical display.
Fig. 2: Image of a Digital Panel Voltmeter
The ADC is generally known as Dual Slope converter or Integrating Converter and is immune to noise. The ADC works in two stages:
Fig. 3: Image showing Dual Power Supply Circuit