Tomorrow / HW6

I think we should put off HW6 until this coming Wednesday (19 Oct), I don't feel like we've covered magnetism well enough yet. So, no HW due tomorrow.

As a result, tomorrow we'll do a little new material (Ampere's law, current loops & solenoids) and go over a few of the HW problems.

HW6 is out

I know you're excited.

Tomorrow's lecture/lab

Having mastered the blinkenlight, tomorrow you'll build an amplifier/filter out of op-amps. Check it out.

We'll spend a little bit of the lecture-type period with me introducing new material, but the bulk of it on working out and discussing homework problems.

HW5 / today's lab

Since I have delayed our discussion of magnetism, HW5 is delayed from this Friday (30 Sept) until next Wednesday (5 Oct).

In today's lab (and the last part of lecture) we investigated a comparator-based relaxation oscillator. You will probably want to read over how it works a few times to make sure you get your head around it - it is a bit subtle. The important thing is not so much that the circuit oscillates, or that we can make a light blink on and off (we could already do that), it is the general idea of feedback. That is, the circuit is configured in such a way that past output affects present operation, and this allows us to do exceedingly clever things. We'll see this more and more when we discuss op-amps next week. 

HW5 is out

Here it is. I think it is a bit shorter than average, but I am probably not the best one to judge.

For tomorrow's lab, you will be designing and building a variable current source out of an npn transistor, a few resistors, and a potentiometer. You will verify that it operates as expected by checking its performance for various load resistances at fixed supply voltage, and then by verifying for a fixed load its behavior as a function of supply voltage. You will probably need to make use of the notes.

Friday's class

Friday's class will be mostly devoted to going over homework problems. I think most of them should be able to get a decent start on at least, but we'll go over most of the problems in class (at least setting them up).

If there is time remaining, we'll look at a few more transistor circuits to figure out how they work. 

HW3 solutions

Here you are.

HW4 is out

HW4 is out, consisting mostly of problems on resistance and simple circuits. 

Random HW3 hints

Massive hints for your imminent HW set:

HW3 out, HW2 solutions

Here are HW2 solutions. HW3 is now out as well, due Monday 12 Sept.

HW2 number 8

For question 8, you will need to sum an infinite series. It is in fact a very famous and neat little result, which you can find here.

HW2 / today

This afternoon, from 2pm onward, I'll be in or around my Bevill office (room 2050) if you have homework questions. You can also email/text me if you like.

Some of the problems on HW2 are well known (i.e., you could potentially google solutions or hints), some I have asked before in either PH106 or PH126. Just throwing that out there.

Lastly, in general if a HW problem suggests a particular method of solution, but you think you have a better way to get the same result, you can use your own method if you like. For instance, on #2 of HW2, you might decide it is just easier to superimpose the fields of two lines an a semicircle, since the field from those objects are well-known results, rather than setting up the problem as suggested. In general, any consistent method is fine, solutions by any means necessary. This means writing code or numerical solutions are fair game in general [but you should turn in the code with the rest of your HW].

HW2 / HW1 solutions

HW2 is out, due this coming Friday (not Wednesday, as implied by the calendar).

HW1 solutions are also out.

HW2

HW2 will come out some time today Sunday ... due this coming Friday.

HW1

By the way, I should mention that professors in general have a habit of recycling problems that they like. Maybe from the same course, maybe from a similar one ... but if it were me, I would try googling key phrases plus the professor's name. That, and just checking last year's problem sets.

I won't reuse problems a lot, but given that I (a) assigned homework on the first day, and (b) made it due on the second day, I thought I should give you a fighting chance.

Friday's class

Friday, we'll be starting to discuss electric forces and fields. We'll skip most of the beginning of chapter 21 in your text, since it is fairly descriptive stuff you can easily read about, and dive right in to calculating electric forces. This would be the last few sections of Ch. 21, and the beginning of Ch. 22. I'll go over some questions on the HW set as well.

If you're having trouble remembering some of the vector manipulation, I did write a short math guide some time ago (and never quite finished, but close). Hopefully the quick tour of vectors on Wednesday didn't scare too many of you away ... we will start out slowly and work our way up to the harder things.

For Monday, you should have already read Ch. 21 and 22 (or skimmed them at least, let's be realistic here).

HW1

Classes haven't yet started, but I already have your first homework set ready to go ...

Find it here, due Fri 26 Aug before midnight. I know that only gives you about 3 days, but it is very short. There are only four problems, and three of them are just math review. Only the fourth relates to material we'll cover in Wednesday's lecture (or see Ch. 21 in your text).

Anyway: I'll field any questions you might have about them in Friday's class.

Half-serious assignment: get yourselves on Google+ if at all possible. I think the 'hangouts' feature would be nice for office hours, and may try it. I have invites.

Homework (partial) Amnesty Day

Any late homework you get to me by 5pm this Wednesday will be graded at 75% of full points. Last chance.

Next homework

Here's the exam you just took. It is also your next homework, due 20 Nov 2009.

Recall that you have an outstanding homework at the moment. It is OK if you turn that in on Monday.

HW8

Finally, it is out. Relatively short, due at the end of the week.