DAY 4: Nodal Analysis/ Temperature Measurement System

NODAL ANALYSIS

Today we have a quiz. This is a about solving the voltage drop in the circuit which will be expressed by known elements in the circuit. With the previous KCL and KVL method, the algebra of the quiz is kind of complex. However, this is the good example for the new method that will simplify the algebra of the problem, the nodal analysis. 

TEMPERATURE MEASUREMENT SYSTEM

After the quiz, we perform the Temperature Measurement System lab. The professor Mason begin the lab with the hook about the technology in a 3-D printer. This technology is the application of the resistance change in respect to the temperature. 

The explanation about the rate change of  voltage (V/bit). 

The expression for the rate change of temperature ( Celsius degree/bit)

The analyze the circuit to determine v(out) as a function fo R(th) and R. From the equation on the whiteboard verify that v(out) increases as temperature increases. Based on the given graph resistance vs. temperature, we get the termperatur at 25 Celsius degree adn 37 Celsius degree. According to our analysis, we find that R = 4k Ohm and R= 18k Ohm will satisfy the requirment( which we change to  0.4 V voltage change to get the valid R). 

The set-up for this lab based on the diagram. 

The record of resistance at the room temperature (25 C) and at firmly holding (33C). R(th 33C) = 7.3 Ohm and R(th 25C) = 10.95. the record of the voltage response to the specified temperature change. As the results showing, the circuit's performance is almost the same as the design specification with 0.53V voltage change. The percent error is 32.5%,  

The video demonstrating the operation of our set-up

Post-lab activity: The value of R that make delta V maximum is R= square root (R(th1) * R(th2)).

After the experiment, we study about the nodal analysis. This method helps to simplify the equation in the questions like the quiz. We do a nodal analysis problem to practice this method

Summary:

The most important things we learn today are the nodal analysis method and the practical problem in the "temperature measurement system" lab. With the nodal analysis, we can approach to the particular circuit problem more easily. Besides, The lab activities help us improve our intuitiveness and thinking relating to the engineering problems.