Here is simple ICL7017 digital voltmeter circuit easy to build and cheap because it is high technology, by single IC,small number, along by LED 3 digit.
My son want to make a simple DC voltmeter on 0-10V range by Convert a galvanometer to voltmeter.Galvanometer DC1mA is cheap and easy with one resistor only.
Sometimes, we need to measure a too tiny AC voltage level. And high frequency too. Ohh... We cannot use general multimeter. I recommend you try watching the AC millivoltmeter circuit.…
This is Diy digital voltmeter panel meter 0-50V is 0-50V scale. Display with LED 7 segment. In cost 3$ dollar only, builds simple regulator dc power supply
This is Simple LED voltmeter circuit using LM3914, can measure any volts 1.2V to 1200V on 3 range with 10 LED display easy to look and use 9V battery