Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

resistance in voltage measurement path, work around.

Status
Not open for further replies.
Z

zoulzubazz

Member level 5
Joined
Apr 26, 2012
Messages
87
Helped
3
Reputation
6
Reaction score
3
Trophy points
1,288
Activity points
2,040
hey guys, so here is my problem, should be fairly simple but my intelligence is on a strike, could be yesterdays beer.



the idea is to find impedance Z.i am using the 500ohm series resistor to find the current I flowing through the circuit(by messuiring V2). now in the path to measure V1 (across Z) there is a 80 ohm resistance which would obviously bias the value V1 across Z and give me the wrong V1, hence a wrong estimate of Z. how do i compensate for this 80ohm resistence in the measurement path??

Thank you very much.

zoul
 

If you measure V1 with a DVM, this will have a 10 megohm input impedance so the extra current, will be very low, and as you know its a 10 megohm resistor you can compensate for it in your calculations.
Frank
 
The diagram shows ambiguous locations for measuring V1. Does it include the 80 ohm resistor?

If it does not include it then the problem is greatly simplified, and the 80 ohm is there just to throw you off for a minute.

Hint: the current through the 500 ohm is the same current through Z.
 
hello guys,

the voltage measuring setup across Z has a input impedance of 1Gohms. So am i right in assuming there is essentially no current flowing through the 80ohm resistor as sunnyskyguy said and the measured voltage V1 across Z would approximately be the same with and witout the 80ohm in the voltage measurement path?? thanks
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top