I know that a capacitor does not allow charge to flow through it because its two conducting plates are separated by a dielectric (insulating material) but then how does a current flow through a circuit? Is it because at a certain DC voltage (almost like a breaking point), the insulating material in between the conducting plates breaks down and the voltage is able to pass through? I read this online in a scientific forum, but I just wanted to clarify that this is correct. Can someone please provide me with a thorough explanation? I want to make sure I have my basics down correctly. Thank you everyone for your help.
Can someone also tell me if this amount of voltage varies from one circuit to another? If so, how would you know? Is this an explanation for the bulb not lighting up in a simple circuit where the capacitor is after the switch (which is also right after the battery), but before the bulbs? Thank you very much.
The charges do not have to flow "through" the capacitor. They merely flow into one side of the capacitor, building up the voltage as long as they flow and build up. If the voltage on the capacitor is not changing, then no current is flowing into or out of it. The capacitor is a storage device for charges, sort of like having a tank of water on your roof. As long as you pump water up to the tank, there is a flow, and the water gets higher in the tank increasing the potential energy. Just like the capacitor you can then get flow out of the tank later after turning the pump off.
If you turn the switch off, there is no flow and the bulb can not light. That is just like turning a valve off in the pipe to that tank in your attic. You still have voltage, but no current.
But I still do not understand how the bulbs will light up if the charge is being stored on one side only ,and the bulb is closer to the other plate on the other side of the capacitor?
Great question! Let's dive into the basics of current flow in a circuit.
In a circuit, current refers to the flow of electric charge through a conductor. To understand how current flows, it's important to consider the fundamental components of a circuit: voltage, resistance, and conductors.
Voltage, measured in volts (V), is a measure of electric potential difference. It provides the "push" or the driving force that allows charges to flow in a circuit. Think of it like water pressure in a pipe - higher pressure allows water to flow more easily.
Resistance, measured in ohms (Ω), represents the opposition to the flow of current in a circuit. It can be thought of as a blockage that hinders the movement of charges. Conductors, on the other hand, have low resistance and allow current to flow more easily.
Now, let's address your question about capacitors. A capacitor is a passive electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material called a dielectric.
When a voltage is applied to the two terminals of a capacitor, it causes a charge to build up on the plates. The dielectric material prevents the charges from flowing directly between the plates.
In a DC circuit with a constant voltage, charges do not flow through the capacitor as you mentioned because the dielectric acts as an insulator. The charges accumulate on the plates, creating an electric field between them.
However, in certain situations, such as when an alternating current (AC) voltage is applied, the electric field between the plates can undergo periodic changes. This allows charge to flow back and forth through the capacitor, resulting in an alternating current.
So, to summarize, the insulating material in a capacitor (dielectric) in a DC voltage situation does not "break down" to allow current flow. Rather, in the presence of an alternating current or changing voltage, the electric field between the plates of the capacitor mediates the flow of charge. The capacitor stores and releases charge as the voltage across it changes over time.
I hope this explanation clarifies the concept for you!