You are Here: Home >< Physics

Electronics - Series/Parallel Circuit Question Watch

1. Hi there,
Im working on this question but I've confused myself more by watching videos. I'm not sure if the circuit is in series and parallel or just parallel.

I understand the 2.5k Ohms and 1.4k Ohms are in parallel. So is the total parallel resistance in parallel to the 1k Ohms? Or is it in series?

So what i did was:
To work out the current across each resistor i divided the supply voltage by each resistor value:
18/1000
18/2500
18/1400
So does that equal the current drop across each resistor
Then i had to work out the voltage drop which is the same? So i put 18V for all of it

My main worry was if i want to verify and work out the total resistance is it ;
(1/2500 + 1/1400 )^-1 to reciprocate it and then + 1000 = 1897.43..Ohms
OR
(1/2500 + 1/1400)^-1 and then + 1/1000 and reciprocate = 472.97 Ohms

Thanks
2. (Original post by Choco-Omar)
Hi there,
Im working on this question but I've confused myself more by watching videos. I'm not sure if the circuit is in series and parallel or just parallel.

I understand the 2.5k Ohms and 1.4k Ohms are in parallel. So is the total parallel resistance in parallel to the 1k Ohms? Or is it in series?

So what i did was:
To work out the current across each resistor i divided the supply voltage by each resistor value:
18/1000
18/2500
18/1400
So does that equal the current drop across each resistor
Then i had to work out the voltage drop which is the same? So i put 18V for all of it

My main worry was if i want to verify and work out the total resistance is it ;
(1/2500 + 1/1400 )^-1 to reciprocate it and then + 1000 = 1897.43..Ohms
OR
(1/2500 + 1/1400)^-1 and then + 1/1000 and reciprocate = 472.97 Ohms

Thanks
The-Spartan
3. (Original post by Choco-Omar)
Hi there,
Im working on this question but I've confused myself more by watching videos. I'm not sure if the circuit is in series and parallel or just parallel.

I understand the 2.5k Ohms and 1.4k Ohms are in parallel. So is the total parallel resistance in parallel to the 1k Ohms? Or is it in series?

So what i did was:
To work out the current across each resistor i divided the supply voltage by each resistor value:
18/1000
18/2500
18/1400
So does that equal the current drop across each resistor
Then i had to work out the voltage drop which is the same? So i put 18V for all of it

My main worry was if i want to verify and work out the total resistance is it ;
(1/2500 + 1/1400 )^-1 to reciprocate it and then + 1000 = 1897.43..Ohms
OR
(1/2500 + 1/1400)^-1 and then + 1/1000 and reciprocate = 472.97 Ohms

Thanks
The 1.4Ohm is in parallel with the 2.5Ohm. This can be treated as one resistor with an effective resistance of some resistance . This is then in series with the 1Ohm resistor.

Calculate the total resistance first, then find the current flowing through the whole circuit.

Then, work use the idea of a potential divider to get the voltage across each resistor.

Finally, work out the current split in the two parallel resistors.

This procedure works for most circuits, you should be familiar with it.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: May 2, 2016
Today on TSR

Last-minute PS help

100s of personal statements examples here

More pressure for kinky sex?

Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Discussions on TSR

• Latest
• See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.