Lab 15: Mat Lab Complex Numbers

Intro

We used Matlab to solve a system of equation with complex numbers.

Lab 14: MOSFET Control of an electric motor

Intro:

The purpose of this lab is to set up a mosfet for speed control of a provided motor.

Open Loop Voltage Control Circuit

The Gate Voltage is about 4V.

Turning the pot controls motor voltage because it regulated the voltage into the MOSFET

It is difficut to control the speed because there in not a linear relationship with V_GS

PWM Chopper MOSFET

Lab 13: 2nd Order RLC Circuits Lab

Intro:

We used this website

http://www.mhhe.com/engcs/alexander2e/netan_tutorials/tutorials/tutmenu.htm

 to learn to solive 2^nd order RLC circuits.

Lab 12: Oscilloscope 101

Intro:

The purpose of this lab is to get introduced to using an oscilloscope.

Exercise 1: Displaying and Measuring a Sinusoid

Frequency 5kHz

Period 0.2ms

Peak to peak Amplitude 5V

Zero to peak Amplitude 2.5V

Anticipated RMS = 5/√2

VDC -10.3mV

VAC=1.855mV

Exercise 2: Including a DC Offset

+2.5V DC offset

DC coupling

AC coupling

The difference between them is the ground positioning

VDC = 2.48 mV

VAC = 1.91 mV

Exercise 3: Displaying and Measuring a Square Wave with offset.

VDC = 2.49 mV

VAC = 3.08 mV

RMS= 5V/200μs = 25000

Exercise 4: Measuring Mystery signals

DC voltage 4V

Frequency 67.56 Hz

Pk-Pk Amp .4V

Lab 11: Capacitor Charging/Discharging

Intro:

The purpose of this lab was to observe the charging and discharging of a capacitor.  We built a circuit with a 9V DC power supply that charges 2.5mj for 20s, and discharges in 2s. The time it takes for a capacitor to charge up is 5τ. Where τ = RC. We will model a real storage capacitor with the figure below and find the Thevenin equivalent.

Data:

W=2.5mj         t= 20s              Vs=9

Vcap = Vs(1-e^(5t/τ) = 9.939

C= 2*W/Vcap^2 = 62.57μF

Charging:

20=Rc*C à Rc=64800Ω

I= Vs/Rc= 0.139mA

P=IV=1.25W

V_final= 8.87

V_final = R_leak / Rc + R_leak à R_leak = 4421353Ω

Charging Process

Discharging:

2=Rd*C à Rd=639.2Ω

I= Vs/Rc= 1.93mA

P=IV=.0125W

Discharging Process

Analysis:

During charging the thevein resistance is found with Vth = R_leak * Rc / (Rc + R_leak) = 63017Ω. During discharging the thevein resistance is 639.1Ω. Vth = Vcap = 9.939V

Lab 10: Op-Amps II

Intro:

The purpose of this lab is to observer the effect of the changing the feedback resisitor on an op-amp circuit with a network of voltages.

Data:

R­₁: 9.80kΩ       R_F 94.7Ω

Vin Desired      Vin Actual Vout Measured V_RF Measured Iop Calculated

Vin Desired	Vin Actual	Vout Measured	VRF Measured	Iop Calculated
0.25V	0.254V	-2.458V	2.458V	0.01mA
0.5V	0.5V	-4.92V	4.92V	0.01mA
1.0V	0.91V	-9.67V	9.67V	0.01mA

I_CC = 1.08 mA              I_EE = -0.97 mA

Vin Desired	Vout Measured	VRF Measured	Iop Calculated	ICC Measured	IEE Measured
1.0V	1.0V	-9.07V	0.01mA	1.08 mA	-0.97mA

Analysis:

The since the op-amp was an inverting one the voltage became negative.  The voltage was also amplified by 10 times.  KCL should apply, but our result was a bit off.  I_CC + I_EE should be 0.  We get 0.11mA.

Lab Op-Amps Extra Credit

Intro:

The purpose of this lab is to use an LM 358 thermal sensor opamp for temperature measurement.  Lm 358 can run 0-5V and can measure 1⁰C  at 10mV.  We want to design an amplification that can measure between 15⁰C to 35⁰C

Analysis:

We were at least come close to room temperature with an error of about two degrees. 

The problem was there were fluctuations of the temperature readings.