Electrical parameters like voltage and current are inherently associated with electronics and with electronic engineers.
Any electronic circuit would be just incomplete without appropriate supply of voltage and current levels.
Our mains AC supply an alternating voltage at the potentials of 220 V, for implementing these voltages in electronic circuits we incorporate DC power adapters which effectively step down the mains AC voltages.
However, most power supplies don't include power monitoring systems in them, meaning the units don't incorporate voltage or current meters for displaying the relevant magnitudes.
Mostly the commercial power supplies use simple ways to display the voltages like a calibrated dial or ordinary moving coil type meters. These may be OK as long as the involved electronic operations are not critical, but for complex and sensitive electronic operations and troubleshooting, a hi-end monitoring system becomes imperative.
A digital volt meter and an ammeter become very handy for monitoring voltages and current perfectly without compromising safety parameters.
An interesting and accurate digital voltmeter and ammeter circuit has been explained in the present article which can be easily built at home, however the unit will require a well designed PCB for the sake of accuracy and perfection.
The circuit employs IC 3161 and 3162 for the required processing of the input voltage and current levels.
The processed info can be directly read over three 7-segment common cathode display modules.
The circuit requires a 5 volt well regulated power supply section for operating the circuit and should be included without fail as the IC strictly requires a 5 volt supply for operating correctly.
The displays are powered by individual transistors which make sure that the displays are lit brightly.
The transistors are BC640, however you may try other transistors like 8550 or 187 etc.