# Thread: combination circuits

1. ## combination circuits

Hello,

I'm sorry if this is not an appropriate question , I just thought one of you might know the answer. In a simple combination series/parallel circuit, which I think this is, what am I calculating the voltage across if there's a voltmeter attached as shown in the diagram? I know V(T), and have calculated I(T), R(T), R(eq) and the current in each of the parallel parts of the circuit. One of the other questions is to calculate the voltage shown and I have no idea how to proceed any help would be greatly appreciated.

Thank you

2. ## Re: combination circuits

Originally Posted by Furyan
Hello,

I'm sorry if this is not an appropriate question , I just thought one of you might know the answer. In a simple combination series/parallel circuit, which I think this is, what am I calculating the voltage across if there's a voltmeter attached as shown in the diagram? I know V(T), and have calculated I(T), R(T), R(eq) and the current in each of the parallel parts of the circuit. One of the other questions is to calculate the voltage shown and I have no idea how to proceed any help would be greatly appreciated.

Thank you
what do you mean by R(eq)??
And do you mean by (T) total ??

One way of doing it is finding the PD across R5 and across R4 and across R3
and subtracting the PD across R5 from the PD across R4 and the PD across R3

Can you do that??

3. ## Re: combination circuits

Originally Posted by puresoul
what do you mean by (eq), (T) ??
Hello,

Thank you for your relpy.

(T) means total, it should have been a subscript IT, VT and such. Req is the series equivalent of the resistance in the parallel part of the circuit.

4. ## Re: combination circuits

Originally Posted by Furyan
Hello,

Thank you for your relpy.

(T) means total, it should have been a subscript IT, VT and such. Req is the series equivalent of the resistance in the parallel part of the circuit.
Maybe if you write the values that you have we could help you more

5. ## Re: combination circuits

Originally Posted by puresoul
what do you mean by R(eq)??
And do you mean by (T) total ??

One way of doing it is finding the PD across R5 and across R4 and across R3
and subtracting the PD across R5 from the PD across R4 and the PD across R3

Can you do that??
Yes I can, thank you. I think my reply and your edit must have crossed each other. I think it's actually VR5 - (VR3 + VR4) or VR2 - VR6.

Thank you for your help.

6. ## Re: combination circuits

Originally Posted by Furyan
Yes I can, thank you. I think my reply and your edit must have crossed each other. I think it's actually VR5 - (VR3 + VR4) or VR2 - VR6.

Thank you for your help.

That's right

7. ## Re: combination circuits

it is critically important to have a solid understanding of the concepts that pertain to both series circuits and parallel circuits.