This is an easy to build, but nevertheless very accurate and useful digital voltmeter. It has been designed as a panel meter and can be used in DC power supplies or anywhere else it is necessary to have an accurate indication of the voltage present. The circuit employs the ADC (Analogue to Digital Converter) I.C. CL7107 made by INTERSIL. This IC incorporates in a 40 pin case all the circuitry necessary to convert an analogue signal to digital and can drive a series of four seven segment LED displays directly. The circuits built into the IC are an analogue to digital converter, a comparator, a clock, a decoder and a seven segment LED display driver. The circuit as it is described here can display any DC voltage in the range of 0-1999 Volts.
Technical Specifications – Characteristics
Supply Voltage: …………. +/- 5 V (Symmetrical)
Power requirements: ….. 200 mA (maximum)
Measuring range: ………. +/- 0-1,999 VDC in four ranges
Accuracy: ………………….. 0.1 %