Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Replies 7 replies
  • Subscribers 33 subscribers
  • Views 1345 views
  • Users 0 members are here
Options
You may also be interested in

Capacitive coupling

Sam Ayre

Hi so I've been doing some research on capacitive coupling and I just wanted to see people's thoughts on my understanding as the stuff out there is a little difficult to follow and doesn't really provide much help. 

So from my understanding capacitive coupling occurs between an energized conductor and a non energized conductor due to the difference in potential difference.  From what I can see this is very similar to mutual inductance I am assuming the key difference is that mutual inductance works by inducing a current where as capacitive coupling works by transferring a voltage. 

Is this correct 

Thank you in advance 

Sam 

Parents
  • 0

    So is it the change in current caused by the AC wave form which allows the current flow through the capacitor due to the constant charge and discharge they might not be the right words but I think it shows my point. 

    Getting there I think. The rubber membrane analogy is a good one I think. As the pressure (voltage) on one side increases the rubber membrane stretches a little and pushes a bit more fluid out of the other side - until the membrane tension and the pressure balance out. If the pressure increases further the membrane stretches a little more and a bit more fluid flows in on one side and the other fluid is pushed out from the other side. Or if the pressure drops the membrane relaxes and a little fluid flows backwards on both sides. So it's the change in voltage (pressure) that drives the current flow. Bigger capacitors allow more current to flow for the same change in pressure.

      - Andy.

  • 0 in reply to AJJewsbury

    Ah okay so as the pressure (voltage) builds in one side of the capacitor it begins to push from one side of the capacitor into the other. Then once the capacitor becomes fully charged as more pressure try to enter the capacitor it pushes some out of the other side basically replacing the existing charge. 

    Would the same thing occur on a DC circuit or does the capacitor just build up until it's full and then discharge once the DC voltage is removed? 

    Thank you for your patience 

    Sam 

  • 0 in reply to Sam Ayre

    Once the capacitor has charged to match the supply voltage, (Q= C/V where Q relates to the number of electrons displaced relative to their at-rest position, C is the capacitance and V is the voltage) current stops *. As the voltage falls, current flows out and the displaced charges relax back to their original places (well more or less, I am ignoring losses)

    Mike.

    actually and amp second = A coulomb of electrons is a lot, about 1E19 of them - that is a 1 and 19 zeros - they are really small.....

Reply
  • 0 in reply to Sam Ayre

    Once the capacitor has charged to match the supply voltage, (Q= C/V where Q relates to the number of electrons displaced relative to their at-rest position, C is the capacitance and V is the voltage) current stops *. As the voltage falls, current flows out and the displaced charges relax back to their original places (well more or less, I am ignoring losses)

    Mike.

    actually and amp second = A coulomb of electrons is a lot, about 1E19 of them - that is a 1 and 19 zeros - they are really small.....

Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines