Simple Circuit Help

[Spitfir3]

Hey guys,

We're just doing capacitance on simple circuits but i'm having a bit of trouble grasping it

I get the basics but i've got a few questions here that confuse me slightly. Someone told me you have to work on the capacitors furthest away from the terminal then work your way in.

So this one is (1/2 + 1/3)^-1 + 4 = 1.2 μF ?

(2+4) = (1/6 + 1/3)^-1 = 2μF?

This one's confusing me, is it:

C1 and C3 are in parallel, add them together and then say that Ctotal is in series with with C2 but parallel with C4?

Is there a good methodology for working through these?

Cheers

 

[Antar Bolaeisk]

Yep, all correct including how you would go about answering number 3.

 

[Spitfir3]

Yep, all correct including how you would go about answering number 3.

Cheers, any tips on no.3 then? I don't know where to start!

Edit, is it 3.3 recurring μF?

 

[Antar Bolaeisk]

That's what I'm getting.

I've no method to be honest. I try to group them together as much as I can. In this case C1 and C3 group together to form one equivalent capacitance which is then used to calculate the rest of the circuit capacitance.

 

[R.C.Anderson]

Circuit 3:

Combine 1&3 via parallel rule, then add 2, as it's then series with the 1&3 combined, then parallel that with 4, should get you your answer

EDIT: It might help to draw the circuit out at each point, then it's easier to see which are parallel, and which are series, but the rule you mentioned before it correct, start working from those furthest away from the terminals.

 

[Dr.EM]

So this one is (1/2 + 1/3)^-1 + 4 = 1.2 μF ?

Remember to actually add the 4uF, so it's 5.2uF total here.

Third one I do C1+C3 in parallel = 4uF. 4uF in series with C2. Add on C4, effectively in parallel with the whole lot, observe how it is directly accross the power supply so everything else must add to it.

It's not 3.3uF recurring, but not too far off