resistance

impsick · 28th May 2007, 12:00 AM

sorry for the stupid question but i have a feeling even after i get an explanation it will still baffle me. but at the same time might explain alot to why things are done and how like biasing and stuff to me.

ok i understand that if you take 2 resisters of the same rsistance and ruin them side by side, parallel, you get a resistance of half the one resister. example say 1.6k + 1.6k would equal 800ohm. i mean thats a given.

what gets me is sasy you take that 1.6k with a 100ohm you would get a resistance of 100ohm. why? ok yeah the electrons like the shortest fastest rout but why?

or is my meter just a piece?

Conrad Hoffman · 28th May 2007, 12:04 AM

Actually you should get about 94 ohms, the product over the sum. A good DVM will resolve way better than this, but an inexpensive or analog meter might not.

impsick · 28th May 2007, 12:07 AM

sorry that is what i get 94 ohms. what do you mean product over sum?

sandyK · 28th May 2007, 12:16 AM

You multiply the 2 resistor values, then divide by the added values of the 2 resistors. e.g. If you parallel 1Kohm and 10Kohm,
you get 10Kohm DIVIDED by 10,000+1,000(11,000)
The result is 909 ohms
SandyK

CBS240 · 28th May 2007, 02:05 AM

Also

Rt=((R1^-1+R2^-1+R3^-1...+Rn^-1)^-1)

impsick · 28th May 2007, 05:39 AM

word. thanks guys. I got it now.

Nordic · 28th May 2007, 06:01 AM

Jees !!!!!!!! Easy with the hard math....

for 2 resistors

(R1 x R2) / (R1 + R2)

myhrrhleine · 28th May 2007, 04:41 PM

Quote:

Originally posted by impsick
sorry for the stupid question but i have a feeling even after i get an explanation it will still baffle me. but at the same time might explain alot to why things are done and how like biasing and stuff to me.

ok i understand that if you take 2 resisters of the same rsistance and ruin them side by side, parallel, you get a resistance of half the one resister. example say 1.6k + 1.6k would equal 800ohm. i mean thats a given.

what gets me is sasy you take that 1.6k with a 100ohm you would get a resistance of 100ohm. why? ok yeah the electrons like the shortest fastest rout but why?

or is my meter just a piece?

Electricity does not follow the shortest path, or the path of least resistance, but rather all available paths according to their resistance.

a 1.6k resistor allows x current to flow.
Two 1.6k resistors will allow 2 times the current to flow, equol to one resistor of 1/2 the resistance or 800 ohms.

1.6k in parallel with 100 ohms would have the current of the 100 ohm plus the current of the 1.6k resistor, or about equal to one resistor of 94 ohms.

1/R + 1/R +1/R... =1/Total

28th May 2007, 12:00 AM	#1
impsick diyAudio Member Join Date: Dec 2006	resistance sorry for the stupid question but i have a feeling even after i get an explanation it will still baffle me. but at the same time might explain alot to why things are done and how like biasing and stuff to me. ok i understand that if you take 2 resisters of the same rsistance and ruin them side by side, parallel, you get a resistance of half the one resister. example say 1.6k + 1.6k would equal 800ohm. i mean thats a given. what gets me is sasy you take that 1.6k with a 100ohm you would get a resistance of 100ohm. why? ok yeah the electrons like the shortest fastest rout but why? or is my meter just a piece? __________________ "Nothing happens for a reason. There are just reasons why things happen." Quote me on that. http://stores.ebay.com/AudioGrade?_rdc=1

28th May 2007, 12:07 AM	#3
impsick diyAudio Member Join Date: Dec 2006	sorry that is what i get 94 ohms. what do you mean product over sum? __________________ "Nothing happens for a reason. There are just reasons why things happen." Quote me on that. http://stores.ebay.com/AudioGrade?_rdc=1

28th May 2007, 12:16 AM	#4
sandyK diyAudio Member Join Date: Apr 2007 Location: Sydney	Solid State > resistance You multiply the 2 resistor values, then divide by the added values of the 2 resistors. e.g. If you parallel 1Kohm and 10Kohm, you get 10Kohm DIVIDED by 10,000+1,000(11,000) The result is 909 ohms SandyK

28th May 2007, 02:05 AM	#5
CBS240 diyAudio Member Join Date: Aug 2005 Location: K-town	Also Rt=((R1^-1+R2^-1+R3^-1...+Rn^-1)^-1) __________________ All the trouble I've ever been in started out as fun......

28th May 2007, 05:39 AM	#6
impsick diyAudio Member Join Date: Dec 2006	word. thanks guys. I got it now. __________________ "Nothing happens for a reason. There are just reasons why things happen." Quote me on that. http://stores.ebay.com/AudioGrade?_rdc=1


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28th May 2007, 12:04 AM	#2
Conrad Hoffman diyAudio Member Join Date: Mar 2007 Location: Canandaigua, NY USA	Actually you should get about 94 ohms, the product over the sum. A good DVM will resolve way better than this, but an inexpensive or analog meter might not.

28th May 2007, 06:01 AM	#7
Nordic diyAudio Member Join Date: Sep 2005	Jees !!!!!!!! Easy with the hard math.... for 2 resistors (R1 x R2) / (R1 + R2)

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