Bo Zhang

Why the artifact is included: 

It is important to test theoretical knowledge gained in classes to practical applications. One case of this was in electronics lab where we built oscillator circuits. This electronics lab about oscillators can show that I grasp contents of circuit theories well and I have good hands-on skills. Since this lab is a teamwork assignment, it can also show that I have good skills of interpersonal communications.

Descriptions of this project: 

In this lab, we need to design and build a simple relaxation oscillator on a protoboard. The goal is to get a symmetric square wave output, and modify this design to create a triangle wave output. A relaxation oscillator is a Schmitt trigger that uses its output voltage to charge and discharge a capacitor. The voltage across the capacitor is used as the input signal to the Schmitt trigger, creating a circuit that creates a constantly oscillating output.

How artifact relates to the engineering process: 

I followed my engineering design process to do this lab. There are differences between theoretical calculations and real situations. The theoretical calculations ignore the resistance or capacitance of wires and noise of signals, which should be considered in real circuits. For instance, in order to get a specific frequency of a signal, I calculate R = 30 k ohms. Sometimes this value can only be an initial guess because that resistor cannot let the circuit produce the signal I want. That is why I need to spend more time on the fifth step of engineering process, explore possibilities. I remember I switched resistors several times from tens of kilo ohms all the way down to hundreds of ohms. In addition, it always takes me more than one time to get the output because sometimes I forget to connect one pin to ground, sometimes I connect a wrong pin number of chips, etc. So it also takes some time to actually build a functional circuit which is the step seven of engineering design process.