05-19-2016

Lab: Op amp Relaxation Oscillator

I. Introduction:

With our lessons learned from the previous lecture, today we first reviewed how to convert between the wave length and frequency, assume our waves have speed of light 

Given the wavelength, we have to calculate the frequency

II. Op amp relaxation oscillator:
A relaxation oscillator is constructed using some type of device that act as a switch when a certain voltage is applied to one of its terminals. They must meet the following criteria:
1. The overall phaseshift must be zero
2. The unity must be one or greater (to be compensated by the amplifying device)

Here the period is about 8ms,the percent error of experiment is about 7%

Here is the setup of our circuit

Here is our derivation to find the gain beta which is half given that R1 and R2 the same 

Using trig identities to derive an equation for power

We used every circuit to make sure that we have correct graph in the oscillator graph of analog discovery

We were given some problem to find the equivalent impedance in the circuit. in this case, we took away the wire in the middle because there is nothing between it

III. Conclusion:
Today we did some more practice about the mesh and nodal analysis in AC circuit. For the lab, we did the op amp relaxation oscillator. Oscillator is a setup acting like a switch when a certain voltage is applied to one of its terminals. We also find the average power Pave=0.5 Vm*Im*cos(theta v-theta i)