Meeting 14:

We did circuit analysis with LabVIEW II, in which we made a Virtual Instrument (VI) that produced the current I (unit is A for amp) that goes through a circuit with two resistances in series (one after the other) R₁ and R₂ (units are Ω for Ohm) when a battery voltage V (unit is V for volt) was applied. The three input elements (V and R₁ and R₂) are implemented with Numeric Controls, and the two output elements, I and V₁ –the voltage across R₂, were implemented with two Numeric Indicators. Then equations are I=V/(R1+R2); and V1=I*R2.

We then made a VI that produced the current I that goes through a circuit with two resistances in parallel (a same voltage is applied across both of them). The equation was I=V/(R1*R2/(R1+R2)).

Logbook

Just to remind that the logbook is a very important component of the course and will be evaluated, together with the final exam they count 20% of the course grade.

You should record the logbook on a daily basis, with pages numbered and dated, about two main topics:

-Discussions and findings about projects, collectively or individually

-Answers to questions posted here in the class notes and other learning conclusions you found by doing activities related to this course.

The next logbook due date is March 23, 2006.

Logbook questions:

1-Assume a V=9V, R1=R2=1 Ω; what was I for the series and for the parallel combination?

2-By playing with these Virtual Instruments, and knowing that the electrical power consumed in a resistor is P=IV=I²R, what combination will give us the brightest lights, assuming each resistor is a light bulb?

3-What is the current through each resistor in the series and in the parallel combination (for the same V,R1,R2 as in 1)