Experiment 8 Report

# Experiment 8 Report - Experiment 8 Op Amp Design Project...

This preview shows pages 1–4. Sign up to view the full content.

Experiment 8 Op Amp Design Project: “Temperature Sensor for Display and Control” Eugene Gallagher Introduction The basic challenge in this design is to convert the current from the temperature sensor (1 ºK = 1uA) into a voltage. More specifically, we want two separate voltages, one which is .01* ºK and the other .1* ºF. Then in the second part we need to design a temperature controller that will light up a red LED if the temperature drops below 68 ºF (6.8 V) and green if it goes above 72 ºF (7.2 V).

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Schematic 1: Temperature Sensor for Display and Control Circuit Design and Analysis For the circuit design, we used LF412 operational amplifiers. Signal Conditioning for ºK: In order to model the temperature sensor output, we simply used a DC voltage source with a 10 kΩ resistor, which means a 1 V input will produce 100 uA (this should correspond to 100 ºK). We used a simple inverting amplifier used as a current to voltage converter, where V O / I S = - R F. Since we want 0.01 ºK at the V 01 output when I S = 1 uA, R F should be 10 kΩ. This is an inverting amplifier, so in order to get a positive voltage we simply reversed the polarity of the DC source, so the positive terminal was toward ground (I S would be going toward ground). In order to adjust for any error, we had to incorporate a +-1 ºK offset adjustment. This was done by adding a 1.5 MΩ resistor connected to the inverting terminal, then
connecting the other side of the resistor to the center pin of a 10 kΩ potentiometer. The other pins of the pot were connected to +15 V and -15 V respectively. This is modeled on the schematic as a simple voltage divider with 5 kΩ resistors. By choosing a 1.5 MΩ

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern