The LM3915 is a standard IC which drives 10 LED's from a varying voltage, but you don't make it very clear what you want!. What are you wanting to measure?, impedance (as your question suggests), or AC voltage (with the meter giving a high impedance load) - or something else entirely!.
It also helps if you enter your location in your profile, then we have a clue if English is your first language or not! - I'm presuming not?.
Well you should take Nigels advice... But I will venture a guess and
assume you are talking about a voltage meter that has a high input impedance so as not to load the circuit you are measuring and the output of the voltmeter will be some small number of LED's showing you approximately the voltage level you are measuring.
Look here for a simple design using an LED driver chip. Input impedance is not what I consider high though. (but it could be modified to be such)