Hi Guys. I am looking for a sample of an auto impedance circuit and how it will function. I was searching on the internet but found none. Can someone give me a sample of this kind of circuit and how it works?...Thanks

 

Is this related to your other thread? - http://forum.allaboutcircuits.com/showthread.php?t=49625

 

Is this related to your other thread? - http://forum.allaboutcircuits.com/showthread.php?t=49625

No. It is not related to my other thread. For this thread I want to know how to use the auto impedance circuit since this is the first time I learned about it. The other thread, I am trying to find a way to measure inductance, capacitance and resistance.....

 

Now I've never heard of an Auto Impedance circuit. You might get more help if you explain what you think it is and what you need it for. We might actually know it by another name. This is especially true for translations form other languages. If we don't know where you are from it is hard to speculate on this possibility.

 

Now I've never heard of an Auto Impedance circuit. You might get more help if you explain what you think it is and what you need it for. We might actually know it by another name. This is especially true for translations form other languages. If we don't know where you are from it is hard to speculate on this possibility.

It is hard for me to explain what it is since I don't have any idea about it but to my understanding, it is like a Wheatstone bridge circuit I am just not sure. I need it to measure a very small resistance to get the value of any path resistance...

 

The use of the word impedance implies the presence of reactive components like inductors and capacitors. If you are working only with resistance, then that is different. Measuring a small resistance is not remarkably different from measuring any other kind. The purpose of a bridge circuit is to compare an unknown resistance value to a known one. Two identical circuits with the same currents and voltages MUST have the same resistance.

I am curious about the meaning of "Auto Impedance Circuit" -- Anybody?
BTW, congratulations YOU are the #1 Google Hit. Not an easy feat in this day and age.

 

I thought he meant auto-ranging or auto-balancing, but apparently that is not the case. The other thread cited by beenthere addresses those aspects. I guess this thread could be called a double-blind question -- neither the OP nor anyone on the forum seems to know what the question is.

John

 

That is the reason why I said in my previous post that I am not sure how the circuit works, my goal for now is to measure a very small resistance but if the design will work then we will apply it to measure the impedance of capacitors and inductors. The wheatstone bridge is just an idea to start with the design but I am not sure if that will work. Sometimes we call it auto balance circuit. I dont have any idea on how to make the design, I have made several research but found none. If I cant find any idea on how to make the circuit then I guess I just have to stop making the design....

 

Perhaps auto is a reference to a car?

 

Perhaps auto is a reference to a car?

Nope. It is a reference to Automatic....

 

Engr: I think you need to think about what you actually want. Is that auto impedance circuit something you heard about and want to build it?
Or do you just want to build an autoranging RLC meter?

 

Engr: I think you need to think about what you actually want. Is that auto impedance circuit something you heard about and want to build it?
Or do you just want to build an autoranging RLC meter?

The RLC Meter is a different project, but if the auto impedance circuit can be applied to the RLC Meter and it will make the meter more accurate then I guess I will apply it. For now I don't have any plans on incorporating the auto impedance circuit to the RLC Meter.

 

So the term auto impedance is something you call it, or someone told you that? Either say what it is supposed to act like, or ask the guy who told you about it what it is.

This is what I found for automatic impedance, and I don´t think any of those is the right one.
- automatic impedance detection in cables
- automated measurement of pcb traces
- medical works in audiometry

 

Look up "auto-balancing Wheatstone bridge."

You will find, among many other hits:
http://literature.agilent.com/litweb/pdf/5968-4506E.pdf

That particular design seems to be the subject of this thread:
http://forum.allaboutcircuits.com/showthread.php?t=45817

John

 

This has more info:
http://cp.literature.agilent.com/litweb/pdf/5950-3000.pdf

 

Thanks guys. The notes really helped me a lot. I appreciate it. Just have to consolidate all the notes to come up with a good design...