# Design of an Op-Amp Circuit

Discussion in 'Homework Help' started by Ricky Sum, Jun 13, 2016.

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1. ### Ricky Sum Thread Starter New Member

May 6, 2016
13
0
I HAVE A PROJECT BUT NO IDEAS START FROM WHERE, BELOW IS THE QUESTION

Given that the pressure sensor produces an output voltage (Vs : sensor output voltage) according to the equation Vs = (P x 0.131 )+ 1.683. This equation can be expressed in terms of pressure (P) versus sensor voltage (Vs). ie.
P = (Vs - 1.683)/0.131

You are to design the amplifier circuit for this sensor using any combination of inverting amplifiers, non-inverting amplifiers, summing amplifiers together with a 1V reference voltage source. The two input signals of this circuit are sensor voltage (Vs ) and an 1V reference source (Vref ) and the circuit should produce an output voltage (Vo) indicating the pressure (psi) according to the equation Vo = P (psi)

i.e When P = 0 psi , Vo = 0V and
P = 10 psi, Vo = 10V.
P = -10 psi, Vo = -10V.

STANDARD VALUES FOR RESISTORS AND CAPACITORS
(a) The standard E-12 values for fixed resistors are in the following ratios: 1 : 1.2 : 1.5 : 1.8 : 2.0 : 2.2 : 2.7 : 3.3 : 3.9 : 4.7 : 5.6 : 6.8 : 8.2.
Examples: 100, 120, 150, 180, 220, 270, 330, 390, 470, 560, 680, 820Ω OR 1k, 1.2k, 1.5k, 1.8k, 2k, 2.2k, 2.7k, 3.3k, 3.9k, 4.7k, 5.6k, 6.8k, 8.2kΩ OR 10k, 12k, 15k, 18k, 22k, 27k, 33k, 39k, 47k, 56k, 68k, 82kΩ OR 100k, 120k, 150k, 180k, 220k, 270k, 330k, 390k, 470k, 560k, 680k, 820kΩ OR 1M, 1.2M, 1.5M, 1.8MΩ, etc.
(b) The ratios for the standard values of the various types of capacitors are as follows:
(i) pF range – 1: 1.2 : 1.5 : 1.8 : 2.2 : 2.7 : 3.3 : 3.9 : 4.7 : 5.6 : 6.8 : 8.2 Examples: 100pF, 120pF, 150pF, 180pF, 220pF, 270pF, 330pF, 390pF, 470pF, 560pF, 680pF, 820pF, etc. (
ii) nF range – 1: 1.2 : 1.5 : 1.8 : 2.2 : 2.7 : 3.3 : 3.9 : 4.7 : 5.6 : 6.8 : 8.2 Examples: 10nF, 15nF, 33nF, 47nF, 68nF, 82nF, 100nF, 150nF, 220nF, 330nF, 470nF, 680nF, etc.
(iii)µF range – 1: 1.2 : 1.5 : 1.8 : 2.2 : 2.7 : 3.3 : 3.9 : 4.7 : 5.6 : 6.8 : 8.2 Examples: 1µ, 2.2µ, 3.3µ, 4.7µ etc..

1. REWRITE THE EQUATION WITHE INPUT ON ONE SIDE AND OUTPUT ON OTHER SIDE
2. CHOSE THE AMPLIFIERS AND DESIGN
3. SCHEMATIC OR CIRCUIT DIAGRAMS
4. ERROR CALCULATION OF THE COMPONENT (MUST BE LESS THAN 5%)
5. COMPONENT LIST

2. ### ErnieM AAC Fanatic!

Apr 24, 2011
7,953
1,826
You begin by finding the equation that when given the stated inputs from the sensor you get the required outputs. This is simple algebra. Two points make a straight line, you were given three which means you can self check your result.

Solving for Vs in terms of P will show you something importaint.

Last edited: Jun 13, 2016
3. ### RBR1317 Active Member

Nov 13, 2010
417
81
That relation is important, but it is also a given. What is essential is to solve for Vout in terms of Vsensor because Vo/Vs is the transfer function that must be designed into the circuit.