Episode 18: Obey the Laws(of power)

[drandolph]

Calculating resistance and power isn't hard... and, as David explains, knowing Ohm's Law and the Power Triangle can be darn useful when you're designing a project, sorting out power supply issues, or want to keep from burning your car down.

[vincent12234]

Awesome, I'm working with this in collage right now, great to be able to enjoy it for once, awesome episode thanks!

[mawic]

I had to stop watching this episode within the first 5 minuts or so. The AC/DC battle wasnt between Westinghouse, and Edison. It was between Tesla, and Edison; Westinghouse was just a financial geniuis who took advantage of Teslas great mind. Edison used around 6600 VAC to kill the elephant to show that AC was more dangerous. Now I'll return to the show....

[drandolph]

Well you said it. Westinghouse was the financial backer for Tesla but actually the fight was between Edison and Westinghouse. Westinghouse was fighting for Tesla. We should have made that more clear I agree. I would consider it to be in the same class as Jim Louderback and Neil Tiles going at it for Patrick Norton and Kevin Perria as the king of television.

We should have made the fact of Tesla being the man behind the man more apparent.

[marklar]

http://www.uoguelph.ca/~antoon/gadge...rs/ohmslaw.gif

The real ohms law

[scienceking]

Sorry, but as a 4th year Computer Engineering student and someone who has worked with formal electromagnetism derivations since my 3rd year of high school in AP Physics, this episode is by far the worst episode of Systm ever, and probably the worst "day 1" orientation to electronics I have ever seen. Some of the terminology used is awful("wattage" "amperage" in equations, everyone in engineering uses Power and Current). Not discussing the most useful power formulas V^2/R and I^2R.(this is probably the worst part. For ohmic systems P=IV is harder to work with) Not mentioning the R/L + Z linear approximation for line impedances.(I have never heard of anyone using a chart before outside of n00b Mechanical Engineers)

Also whats so hard about finding the energy in a signal? You can just integrate p(t)=i(t)v(t) at the very worst case, and most of the time easier models that fit your situation can just be done by inspection. Also, if you want to talk about not frying your electronics projects, the idea of line impedance over just resistance is important, as line inductance or capacitance can imply nearly infinite(in the model) transient voltages and currents, and these can burn out a PSU easily. See http://www.physics.princeton.edu/~mc...amples/igct.ps for a great example of this big problem.

I'm not sure if this episode is a production value casualty of the new hectic weekly release schedule at R3, but I have to say, after some episodes i thought were great for new electronics learners like the PCB etching episode and the tools episode, this was truly disappointing. Best hope for the future.

[spmion]

I really enjoyed systm when the show was more project-focused. These new theory tutorials have been really hit-or-miss. In the older episodes, I really felt like the hosts dominated the subject matter being presented (eg. MythTV Episode), but lately, it just seems like maybe David and for sure Patrick are operating outside their area of expertise. I've seen enough of David's projects to know that he knows his stuff, and Patrick made it clear to me in the wifi episode that up to the "fresnel" point he's got a lot to offer from his experience base. I just wish David and Patrick would stick to topics they are authorities on, because episodes like this one make me question what I'm really gaining from this podcast.

Looking forward to more great systm projects...

[tempesta]

"not systm, a new show thats coming out on revision3"

gee pat, whatever could you be referring to? :P

Patrick said "if you are watching the HD version....". Is systm going to be in HD soon?

[firefalcon]

Originally Posted by scienceking

Sorry, but as a 4th year Computer Engineering student and someone who has worked with formal electromagnetism derivations since my 3rd year of high school in AP Physics, this episode is by far the worst episode of Systm ever, and probably the worst "day 1" orientation to electronics I have ever seen. Some of the terminology used is awful("wattage" "amperage" in equations, everyone in engineering uses Power and Current). Not discussing the most useful power formulas V^2/R and I^2R.(this is probably the worst part. For ohmic systems P=IV is harder to work with) Not mentioning the R/L + Z linear approximation for line impedances.(I have never heard of anyone using a chart before outside of n00b Mechanical Engineers)

Also whats so hard about finding the energy in a signal? You can just integrate p(t)=i(t)v(t) at the very worst case, and most of the time easier models that fit your situation can just be done by inspection. Also, if you want to talk about not frying your electronics projects, the idea of line impedance over just resistance is important, as line inductance or capacitance can imply nearly infinite(in the model) transient voltages and currents, and these can burn out a PSU easily. See http://www.physics.princeton.edu/~mc...amples/igct.ps for a great example of this big problem.

I'm not sure if this episode is a production value casualty of the new hectic weekly release schedule at R3, but I have to say, after some episodes i thought were great for new electronics learners like the PCB etching episode and the tools episode, this was truly disappointing. Best hope for the future.

Scienceking, while you are correct that the show was sloppy in the way it expressed ideas and often incorrect, the majority of your post was tantamount to the ramblings of a self-diluted retarded person. First, you cite the hosts for their choice in terms while most of your terminology is non-standard for academia or industry. You appear to be trying to think of the biggest words you just learned in class and writing them in your post because you think it makes you look smarter... it doesn't. You say the hosts didn't address, "the most useful power formulas." If you had any experience besides your homework assignments, you would know that the most useful power formulas are dependent on which problem domain one works in. Apparently you also have little experience with the types of projects Systm does. They have little need to ever think of the non-ideal properties of the wires they use. The communication speeds are slow, the voltage levels are low, and current draw is low. The paper that you cited, which I wasted my time reading, had no bearing on anything dealing with this show or Systm in general and appears to me to be a feeble attempt on your part to show that you can find (but apparently not understand) a formal paper. Good luck in getting a job after you graduate.


---Matthew Hicks


University of Illinois
Dept. of Computer Science
Ph.D. Candidate
Real-time, Embedded, and FPGA-based system consultant