resistors in parallel......

[Semidevil]

ok, here is a basic concept that I never got.

if you have a simple circuit w/ 2 resistors in parallel, are the voltages of the 2 resistors always the same? what if the resistors have different values?

 

[JetBlack69]

The voltage is the same, the current across each is different assuming they are different resistors.

 

[lukatmyshu]

Voltage drop across two resistors in parallel is always the same. If you have different values for your resistor you'll have a different current through the two resistors.

 

[pinoy]

its been a long time since i took elec. circuits but i think:

2 resistors w/ diff. values in parallel:

(R1)(R2)/ R1+R2 = R equiv.

 

[Stojakapimp]

Originally posted by: JetBlack69
The voltage is the same, the current across each is different assuming they are different resistors.

bingo....and you had better learn to spot that easily. Determining points where voltages are the same is sooooooo important when solving circuits.

 

[Triumph]

uh huh. learn current divider and voltage divider rules by heart.

 

[pray4mojo]

On a similar subject, what is the purpose of a diode?

 

[jonnyGURU]

Originally posted by: JetBlack69
The voltage is the same, the current across each is different assuming they are different resistors.

Ditto.

 

[Semidevil]

ok, so the voltages are always the same no matter what.......hmm

ok. thanx.

wierd concept.

what if it is like resistors in parallel w/ a cap or an inductor, or a cap parallel w/ an inductor?

does the same concept apply?

also, is there a way to combine resistors and capacitors and inductors in AC circuits??

I know that if I have a 3 ohm resistor in series w/ a j2ohm capactor, the combined would just be 3+j2. what if they are in parallel?

 

[xyion]

Originally posted by: Semidevil
ok, here is a basic concept that I never got.

if you have a simple circuit w/ 2 resistors in parallel, are the voltages of the 2 resistors always the same? what if the resistors have different values?

the voltage drop across the 2 resistors is exactly the same, because they are in parallel. The current is different, because it will always take the path with less resistance.

 

[jonnyGURU]

Originally posted by: pray4mojo
On a similar subject, what is the purpose of a diode?

Restricts current flow in one direction.

 

[JetBlack69]

Originally posted by: Semidevil
ok, so the voltages are always the same no matter what.......hmm

ok. thanx.

wierd concept.

Try to think of the voltage as potential. It has the potential to go through both resistors. The least resistant resistor will have more current than the other.

 

[Stojakapimp]

Originally posted by: Semidevil
ok, so the voltages are always the same no matter what.......hmm

ok. thanx.

wierd concept.

you just gotta remember that all voltage means is potential difference from one point to another. Take a simple circuit with 2 resistors in parallel. On the top, they share the same node. Now if you want to find the voltage across a resistor, it is the potential difference from the top node to the ground on the bottom. Well it's going to be the same way for the other resistor

 

[tm37]

Originally posted by: pray4mojo
On a similar subject, what is the purpose of a diode?

A diode only allows either positive or the negitive charge to go through.

They are used manily in ac to dc convewrters and some other stuff.

<- tech for 8 years who hasn't tested a diode in say about 5

 

[cheapgoose]

Originally posted by: pray4mojo
On a similar subject, what is the purpose of a diode?

current can flow through a resistor in both directions, but diode is like a one way street, current can only travel one way. there's a lot more, but that's the only thing i remember from class.

 

[cheapgoose]

ah man, we have the same quote in our sig.

 

[JetBlack69]

Originally posted by: Semidevil
ok, so the voltages are always the same no matter what.......hmm

ok. thanx.

wierd concept.

what if it is like resistors in parallel w/ a cap or an inductor, or a cap parallel w/ an inductor?

does the same concept apply?

also, is there a way to combine resistors and capacitors and inductors in AC circuits??

I know that if I have a 3 ohm resistor in series w/ a j2ohm capactor, the combined would just be 3+j2. what if they are in parallel?

You have to convert the capactor to it's equalavent resistance (I forget the name) I think, it's been a few months.

EDIT: oh nevermind, I thought the cap was 3+2j, what you said was correct.

 

[cheapgoose]

impedance?

man, so i edit because I thought I spelled impedance wrong. it was right, now that's a first.

 

[JetBlack69]

Originally posted by: cheapgoose
impedance?

yep,

here is a good link

http://www.phys.unsw.edu.au/~jw/AC.html#impedance

 

[MeanMeosh]

current flows through the path of least resistance. so, when it encounter two resistors in parallel, more current flows through the one with lesser resistance. the proportion of current that goes through each resistor, which can be found using the current divider equation, is such that the voltage (v = i * r) is the same through both resistors