# is there a way in which i can calculate resistor values instead of solving this complex equations

#### ashokraj

Joined Feb 1, 2018
137
I am desiging non inverting amplifier with inverting postive reference voltage circuit.
I will have to solve these equations to know the resistor values. is there a way i can solve these equations simply by inserting input voltage range, output voltage range, reference voltage?

#### atferrari

Joined Jan 6, 2004
4,782
Complex? Really?

#### ericgibbs

Joined Jan 29, 2010
18,990
hi,
Set up a Spreadsheet, so that you enter the values and it does the calcs.
E

#### DickCappels

Joined Aug 21, 2008
10,227
What kind of amplifier is this, and where did you get that equation?

#### DickCappels

Joined Aug 21, 2008
10,227

You can make this a lot simpler my looking at the circuit as two circuits and solve each one.

Simply find the values of R3 and R4 to give the offset voltage in the correct proportion to the input voltage. This is a simple resistive voltage divider problem.

After that use the formula below to calculate the resistor values needed to scale the offset signal at the noninverting input to the desired amplitude on the output.

The formula: The output of the amplifier is the voltage on the noninverting input times (1 + (R1/R2)).

/////////////////////////
Gain of a noninvertng amplifier: