Day 25 - Tuesday, May 19, 2015 - There was no lab today

Day 24 - Thursday, May 15, 2015 - Inverting Voltage Amplifier and OP AMP Relaxation Oscillator

Today we did two labs.

For the first one was called Inverting Voltage Amplifier. First we determined the cut off frequency. Second we found the amplitude gain and the phase difference for 3 values of frequencies. This is shown on our picture of the pre-lab below.

Then we set up our circuit and took a couple of pictures.

Then we took data for our 3 frequency values. The first picture shows the voltage out and voltage in when the frequency is one tenth of the cut off frequency.

The second picture shows the voltage out and voltage in when the frequency is the cut off frequency

The third picture shows the voltage out and voltage in when the frequency is ten times the cut off frequency.

Then we recorded the values of gain and phase difference and compared them to our predicted results.

We were pretty close!


The second lab is called OP AMP Relaxation Oscillator. For this one, we combined op amps with capacitors and resistors. There was no source.

First we set up the circuit on everycircuit.com

After we got it working, we built it, and measure the gain of the circuit.

Day 23 - Tuesday, May 12, 2015 - Phasors: Passive RL Circuit Response

In today's lab, we looked at the steady state responses of RL circuits. In RL circuits, the voltage signal that is measured across the inductor is phase-shifted from the the input signal, when the latter is sinusoidal. Also, there is a gain associated with it.

We started with a warm up.

We showed how the formulas for gain and phase shift are derived.

Below is a picture of our circuit:

Day 22 - Thursday, May 7, 2015 - Impedance

Today's lab was called Impedance

The first circuit we constructed had two resistors

The frequency is 1kHz.

The frequency is 5kHz.

The frequency is 10kHz.

 We constructed a circuit with an inductor of 1 microH.

The frequency was 1kHz.

The frequency was 5kHz.

The frequency was 10kHz.

We constructed the circuit with a capacitor of 100nF

The frequency was 1kHz.

The frequency was 5kHz.

The frequency was 10kHz.

Day 21, Tuesday, May 5, 2015 - There was no lab today.

Day 20 - Thursday, April 30, 2015 - RLC Circuit Response

Today's lab is called RLC Circuit Response

Our signal looks like this. 

Day 19 - Tuesday, April 28, 2015 - Series RLC Circuit Step Response

Today we did 2nd Order Circuits. These are circuits with both capacitors and inductors.


When we apply KVL to source free series RLC circuits, we have


s =

We define constant alpha = R/2L and omega_knot = 1/ square root of (LC). Alpha is the damping constant. Omega_knot is the resonance constant.


Now, Napier came up with the damping ratio (zeta) = alpha/ omega_knot

Then we have three types of solutions:

overdamped

critically damped

underdamped

Today we did a lab called Series RLC Circuit Step Response.