Step one for making a multimeter is to build a volt meter. The volt meter circuit is central to all other multimeter functions.
Find a semiconductor and display to only measure voltage. If trying to make a better resolution meter or learn what a meter really does, then do same with an A/D (analogu to digital) converter of at least 12 bits. Your converter will convert an incoming voltage to digital bits representing that voltage. Also learn how an A/D voltage reports different input voltages by using a resistor divider for each voltage scale.
I entered ICL7106 into Google. Got too many datasheets and other discussions. ICL7106 was simply one of so many such such solutions. ICL7106 was also one of the more famous.
In the meantime, you are also learning about Norton and Thevenin equivalent circuits because you asked to build more than just a DC volt meter. Also learn about voltage dividers. If I have not yet said it enough, the number 1 reason why we build things and fix things is to learn. Posted here are things that most any computer literate layman has in his toolbox of knowledge. What you are doing is what an informed computer tech has also done. Learn introductory concepts. And learn how to quickly get knowledge from datasheets.
Your multimeter project, even if you only get it to become a volt meter, is a perfect example of what any technically informed layman should attempt.
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better go for micro controller design, old multi-meters used 7106 but now all are using multimeter and the parts count and the input switches can be reduce, 7106 is good for 3.5digit volt meter but for multimeter you have to add more circuits to it,
better go for micro controller design, old multi-meters used 7106 but now all are using multimeter and the parts count and the input switches can be reduce, 7106 is good for 3.5digit volt meter but for multimeter you have to add more circuits to it,