+ Post New Thread
Results 1 to 3 of 3

8th August 2019, 10:48 #1
 Join Date
 Mar 2012
 Posts
 119
 Helped
 2 / 2
 Points
 1,867
 Level
 10
Isolate R37 from Equation
Hi,
I need to Isolate R37 from the attached Equation.
The Resistors and Vo, Vf,VCC need to be in the equation.
Any Solution?
Thanks,
Doron

Advertisement

8th August 2019, 18:19 #2
 Join Date
 Jan 2008
 Location
 Toronto area of Canada
 Posts
 8,733
 Helped
 2048 / 2048
 Points
 53,610
 Level
 56
Re: Isolate R37 from Equation
R37 is a very important part of the circuit since it and R42 set the input voltage of the opamp, then since the opamp has a gain of 1 the output voltage of the opamp is also set to be the same as the input voltage.

Advertisement

8th August 2019, 18:26 #3
 Join Date
 Jan 2019
 Posts
 358
 Helped
 88 / 88
 Points
 1,911
 Level
 10
Re: Isolate R37 from Equation
try this:
apply voltage divider at the + input of the op amp V+ = ...
assuming a perfect op amp, V and output = V+
combine R25 and R28 to one equivalent resistor
assuming Vo is open, apply voltage divider (Vf, R21, V+ and equivalent R25R28)
when you have Vo = ..., replace V+ with what you got above
follow the rules of algebra
expand everything so there are no parenthesis and no fractions
put all terms with R37 on one side of =, everything else on the other side
factor out R37 and divide
+ Post New Thread
Please login