How to Solve Parallel Circuit Problems in Electronics

[camel-man]

1. Consider a circuit with 3 resistors (250.0 , 150.0 , 350.0  ) connected in parallel with a 24.0 V battery.

Find the total current supplied by the battery.

Find the current through each resistor.




2. I=V/R



3. I know that resistors in parallel must be added up and then inveted like so
1/150 + 1/ 350 + 1/250 then invert the answer. When I do that I get 74. I then add that into I=V/R where V=24 and R=74
My answer I=.324

 

[nrqed]

1. Consider a circuit with 3 resistors (250.0 , 150.0 , 350.0  ) connected in parallel with a 24.0 V battery.

Find the total current supplied by the battery.

Find the current through each resistor.




2. I=V/R



3. I know that resistors in parallel must be added up and then inveted like so
1/150 + 1/ 350 + 1/250 then invert the answer. When I do that I get 74. I then add that into I=V/R where V=24 and R=74
My answer I=.324

What you found is the current through the equivalent resistance. What they want is the current through each individual resistor. Do you know the voltage across each individual resistor? (hint: they are in parallel, so ...)

 

[collinsmark]

1. Consider a circuit with 3 resistors (250.0 , 150.0 , 350.0  ) connected in parallel with a 24.0 V battery.

Find the total current supplied by the battery.

Find the current through each resistor.




2. I=V/R



3. I know that resistors in parallel must be added up and then inveted like so
1/150 + 1/ 350 + 1/250 then invert the answer. When I do that I get 74. I then add that into I=V/R where V=24 and R=74
My answer I=.324

Well, that's the total current through the battery, assuming the battery is ideal and does not have any internal resistance.

The next part of the problem is to find the current through each resistor. (See nrqed's post)

 

[KL7AJ]

A shortcut to doing parallel resistance problems is to use the CONDUCTANCES of each component: (G=1/R). Then you can simply add the Gs of each component. This is what you're actually doing when you use the formula Rt=1/(1/r1+1/r2+1/r3...). But they never tell you how they get that in most electronics classes!

Eric

 

[NascentOxygen]

A shortcut to doing parallel resistance problems is to use the CONDUCTANCES of each component: (G=1/R). Then you can simply add the Gs ...

But they never tell you how they get that in most electronics classes!

With good reason, IMHO. It's too confusing! http://www.clicksmilies.com/s1106/waffen/violent-smiley-049.gif