Today we did Cascading op amps, which is basically putting head - to - tail arrangement of op amps, making the output of one as the input of the other.
The problem given:
Our hand solution:
"Temperature Measurement System Design" Lab:
Prelab:
Designing a circuit which could amplify the voltage difference caused by the thermistor. Whereas the voltage difference from hot and cold from the previous lab ("Temperature Measurement System" lab) was somewhere below .5V, the circuit that we design should provide enough gain to get a voltage difference of 2V.
The wheatstone bridge circuit calculation and design:
Our first hand drawn solution:
This circuit was flawed because instead of grounding the R2, we connected it to the Vout. This design gives out a circuit which would saturate at the slightest touch and would not go back. We realized the mistake that we made, and redraw a new circuit:
Our working circuit:
Our result:
It hits over 2V!!
Our Data and analysis:
Summary:
This lab enables us to make a more accurate device to measure temperature difference. Since the voltage difference is amplified, we could observe smaller difference that happens during the experiment. The hard part about setting this experiment is to make sure the voltage across the wheatstone bridge is 0, which with my OCD personality does not bode too well. It is really important to make sure that it is as close to 0 as possible, though, because the error will be multiplied by the circuit, which would make a high error in the calculation if not careful.
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