Physics question about ohms

bikezappa

Ducati Guy wrote: »

Still pretty confused about watts?

A 120 watt light bulb would have the following volts and amps; 120 volts X 1 amp = 120 watts
A 60 watt light bulb would have the following volts and amps; 120 volts X 0.5 amp = 60 watts
A 240 watt light bulb would have the following volts and amps; 120 volts X 2 amp =240 watts

It's nothing buy math. If you understand the math you are good to go. If your math sucks then you need stories.

Ducati Guy

bikezappa,
nice analogy with the light bulbs,
can you translate that same line of thought to amplifiers for me

BlueFox

BlueFox wrote: »

Yes sir. Whatever you say.

I=E/R. 'I' = current, 'E' = voltage, 'R' = resistance.

'I' is inversely proportional to 'R'. 'R' goes down, 'I' goes up.

Power = 'E' * 'I'

Try doing one research instead of being so lazy.

bikezappa

Ducati Guy wrote: »

bikezappa,
nice analogy with the light bulbs,
can you translate that same line of thought to amplifiers for me

The voltage changes with the volume control on your amplifier but the resistance of the speaker stays the same.

Watt = IxV or volts times amps
Ohms law is V=IxR or amp times resistance = voltage
or I=V/R or volts divided by resistance = amps
Substituting Watt= VxV/R or volts times volts divided by resistance = watts
As you increase the voltage on your amplifier you increase the watts by that simple formula.

I hope I got that right, it's been a few years.

gumbay13

Can you guys speak English please!

All this is Greek to me...sort of

WLDock

Jhayman wrote: »

Yes that's the way I remember it from school the water hose analogy which they also use for explaining how cable Internet works..

The water analogy is one I did not hear about until years after I was out of ET school. Suprising!:surprised:

Ducati Guy wrote: »

Still pretty confused about watts?

Watts is just the unit thats used to measure power.

zingo

I feel like there have been a lot of great examples and help offered, and demanding a further explanation is simply rude. If you, the reader of this thread, are still confused by the math and electrical theories discussed, pick up a book and learn the details the way most of us did. Don't take advantage of the knowledge and generosity of Polkies.

tonyb

Still confused ?

Plenty of examples given both scientifically and in laymens terms. Maybe state exactly what it is you wish to know, about a particular piece perhaps ?

Personally I find that digging too deep into all this just confuses people anyway. Grasp the basic principles of power and once applied should carry you your whole audiophile life.

WLDock

Also, there are youtube video's that cover basic electricty to advanced amp design. Also, I just love this site, it a great resource for learning.: http://www.bcae1.com/ The creator of the site Perry Babin also does repair work.

bikezappa

tonyb wrote: »

Still confused ?

Plenty of examples given both scientifically and in laymens terms. Maybe state exactly what it is you wish to know, about a particular piece perhaps ?

Personally I find that digging too deep into all this just confuses people anyway. Grasp the basic principles of power and once applied should carry you your whole audiophile life.

I don't think this is very deep. Just my opinion. It's an opportunity to un-confuse people maybe. All that is required is the desire to learn while using basic algebra to play with a few simple equations. I first learned this in Vocational school as a freshman in high school back in 62 so I am an old ****. I think the confusion is that you need to go step by step just like building blocks.

There are many basic electric courses on the net that are very good at teaching.

tonyb

I agree pal, but like everything else the process of learning can be hard for some folks. Not insinuating anything either, just that some don't want to include algebra when searching for an amp is all. Keeping it simple, gives them enough info to move forward with some confidence is all I'm saying.

bikezappa

You know some people never get algebra.

My wife is very smart but Einstein couldn't teach her algebra.

mhardy6647

BlueFox wrote: »

Power = 'E' * 'I'

Try doing one research instead of being so lazy.

Actually, it might just be that one of us galoots might explain it a little better in terms of what the poster seeks than all of those Wikipedia articles... or maybe one of us can point him to one that might take a while for him to stumble on via a random walk through google. Might...

Speaking of which... this guy has a passel of primers on hifi basics that I find quite helpful and digestible...
http://sound.westhost.com/articles.htm

Ducati Guy wrote: »

Thanks guys that does help me understand it a little better.
The garden hose analogy helps.

I feel like the couch potato eating Cheetos while watching Stephen Hawkings explain worm holes, " yeah, I get it now as I grab for my 2nd bag of Cheetos".

It's been 22 yrs since my last physics class I had to take in college. I'm a doc not an engineer, so learning these
Concepts is like learning a foreign language, you don't really understand it until you use it.

One more question, so how does amplifier watts relate to all this?

And I am but a lowly biochemist (and I think that cnh is an economist or somethin' like that!) - but I find that the more one understands the nuts and bolts, the more sense stuff makes... I also think forewarned is forearmed, when someone tries to sell you magic pebbles to sit atop your hifi, or "interconnect" cables (patch cords) with AA batteries embedded in 'em...

Ohm's Law gets you at least half of what you need to know if you're a hifi geek :-)

Do you understand how the load resistance (or impedance, in terms of an AC/audio signal) and power are interrelated? I * E = P current times voltage = power All things being equal, more current will flow through a given load impedance at a given potential (voltage)... Power depends on voltage and current, or impedance and current (P = I^2 * R), thanks to Ohm's Law.

BlueFox

WLDock wrote: »

The water analogy is one I did not hear about until years after I was out of ET school.

When I was in Navy Aviation electronic schools they told us little Marines moved the electrons. Also, at the time there was a debate as to whether the electrons flowed, or the holes (where the electron was) flowed in the opposite direction. The answer was holes flowed; every 28 days.

Then there was the memory aid for remembering resistor color codes: BBROYGBVGW; Bad Boys Rape Our Young Girls But Violet Gives Willingly, which is black, brown, red, orange, yellow, green, blue, violet, gray, white. It amazes me I still remember that stuff, but I forget somebody's name 5 minutes after being introduced. I always joke that is why I am a good engineer, and a terrible sales man.

[Deleted User]

Here's a link to an article on this subject written by Paul DiComo (long timers remember "Polk Paul"), Scott Orth (Polk engineer responsible for LSiM among other great designs) and your's truly:
http://hometoys.com/emagazine.php?url=/htinews/feb04/articles/polk/impedence.htm
Enjoy, Ken

mhardy6647

BlueFox wrote: »

When I was in Navy Aviation electronic schools they told us little Marines moved the electrons...

Well... of course... but some folks here aren't ready for the full-on science.

(and I'll defer comment on the other observation and the mnemonic....)

:-)

Ducati Guy

Thanks bikezappa & Kenneth

That helps a lot!
I love that article by Paul Dicoma! This article is absolutely GOLDEN!!
I now feel I have a good basic understanding of ohms.

Peace.

Ducati Guy

Hey Kenneth,
Do you have anymore articles by Paul Dicoma?

[Deleted User]

Hi Ducati Guy,
I'm glad the article was helpful. For several years Polk had a quarterly newsletter and Paul wrote most of the articles. I don't know if they are still available archived on this site or not. Matthew Polk wrote one or two and so did other Polk employees.
Cheers, Ken

mhardy6647

Kenneth Swauger wrote: »

Hi Ducati Guy,
I'm glad the article was helpful. For several years Polk had a quarterly newsletter and Paul wrote most of the articles. I don't know if they are still available archived on this site or not. Matthew Polk wrote one or two and so did other Polk employees.
Cheers, Ken

If not... perhaps you could provide some... encouragement? Persuasion?

;-)

Thanks, Ken, for providing that info.

gumbay13

Kenneth Swauger wrote: »

Here's a link to an article on this subject written by Paul DiComo (long timers remember "Polk Paul"), Scott Orth (Polk engineer responsible for LSiM among other great designs) and your's truly:
http://hometoys.com/emagazine.php?url=/htinews/feb04/articles/polk/impedence.htm
Enjoy, Ken

Thanks for the article.
Now i feel i can wrap my head around this subject.