Impedance meter

[KuRaSsA]

Hi everyone, does anybody know how to build a high impedance meter with leds, i need for a scholar project. I´ll appreciate your help. thanks.

 

[Nigel Goodwin]

Hi everyone, does anybody know how to build a high impedance meter with leds, i need for a scholar project. I´ll appreciate your help. thanks.

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?.

 

[Optikon]

Hi everyone, does anybody know how to build a high impedance meter with leds, i need for a scholar project. I´ll appreciate your help. thanks.

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)

http://www.solorb.com/elect/solarcirc/vom/

another

**broken link removed**

These work over a limited range of input voltages however. You can add some switching & resistors to add some voltage ranges if you like.

If this is what you are talking about, these may be good enough for your school project. If you want to mod them for higher input impedance- just ask.