Sunday, February 10, 2008

Electrical Engineering is Hard

So after a long sit-down with one of my engineer friends at work, I finally had enough understanding to make my first working circuit (an op amp booster w/low cut)! I've been able to play around with it further, as well as incorporate things from other schematics and still have it work, so I'm stoked. It's pretty simple as far as pedals go, but I'm happy to actually have accomplished something now. The hours spent obtaining no result where starting to become very frustrating and VERY un-motivating.

My experience so far with electrical engineering is much harder than my experience with software engineering. It's quite confusing...most of which probably brought on by many incorrect assumptions. In particular, I keep thinking of the flow of the circuit like the flow of an audio signal. Which, in some ways, is very similar if not the same, but it's also in many ways, not the same at all. For example, I was looking at an example schematic of how the TubeScreamer tone control works (I'm not looking to build a tubescreamer...yeck...just looking for academic purposes). The tone control was basically a pot with it's wiper connected to ground through a capacitor...with it's 1 and 3 lugs going from the negative input of an op amp back to the audio input. What I couldn't understand is how this worked as a bi-polar tone control...why does turning it one way roll off highs, and the other way roll off bass...I could only see that it would roll off highs. That is, until I realized that turning the one way caused the audio input signal to flow to ground through that cap too!

I've made up the following mnemonic to help me remember:
"Shit Always Wants To Go To Ground"


I made another trip out to Halted yesterday...god I love that place. They didn't have several of the things I was looking for this time though; particularly nuts to replace those Vector nuts for the rails. Their screw/nut stock ratio is a bit lopsided...many more screws available than nuts. They were a bit short on potentiometers as well... It certainly is *THE* place for resistors, caps, diodes, and transistors though...ICs as well. I'm sure Halted is going to be a weekly visit for a long time to come.

Fun stuff for this weekend is now officially over's time to do the taxes.


Zerosum Inertia said...

That was a really fun post to read,
Mostly because it sounds like stuff I would say.
I agree, although I would like to be able to build my own stuff at some point, I'm not ready now.

surachai said...

At first I thought you were going to blow my mind about how electricity does something entirely illogical. At least it makes sense in the confines of reality and that you don't have to deal with astronomical nor miniscule factors. Make reality your biatch.
Whatever you make, and you're proud of, I'm buying.