- #1
Janez
- 17
- 2
I have question, why can condesator get charged, when connected to voltage source, if for current to flow, there most be closed wire, but here it is not, but there still is current? Thanx for answers.
The plates in the capacitor allow room for the charges to accumulate that a simple wire does not. As long as the charge can continue to flow into the capacitor plate, it seems just like they are going through on a normal wire. Once the capacitor plate is filled up, the charge stops flowing. If the charge changes direction, the accumulated charge flows back out and once again appears as though it is going through a normal wire. So the capacitor plates provide a storage area for charges to come and go. If the charge changes direction often (high frequency), a capacitor acts very much like a simple wire. If the charge doesn't change direction often (low frequency), the capacitor acts more like a disconnected wire (higher resistance).Janez said:Why do we need capacitator then? If the wires are metalic and we have voltage source, we just disconnect wires at some point and wires should get charge on them?
That is too simplistic. If the Capacitor is in a 'black box', you can measure a current flowing into the + terminal and out of the - terminal. If you looked at just the instantaneous current (a single quick reading of IN and OUT)) you would not know what component was in the box and you could even conclude that it was a resistor (of an appropriate value). HOWEVER, over time, the current flowing would be changing (and the PD across it). The slower the changes, the greater the Capcitance.Janez said:if for current to flow, there most be closed wire,
We 'need' Capacitors because we can use this time dependence of Current and PD to cause phase changes, frequency selectivity and timing delays in a circuit which you just can't do with resistors alone.Janez said:Why do we need capacitator then?
Disconnected wires are a capacitor but with very low capacity. If we need more capacity, and we often do, we need to increase the area of the electrodes, bring them close together, and replace air with a better material. All of these increase the capacity.Janez said:Why do we need capacitator then? If the wires are metalic and we have voltage source, we just disconnect wires at some point and wires should get charge on them?
If and when you ever study electric circuits you will quickly see why we need caps.Janez said:Why do we need capacitator then?
A capacitor is an electronic component that stores electrical energy in the form of an electric field. It is made up of two conductive plates separated by an insulating material called a dielectric.
A capacitor works by storing electric charges on its two plates. When a voltage is applied across the plates, electrons from the negative terminal of the power source flow to one plate and accumulate there, while an equal number of electrons from the other plate flow to the positive terminal of the power source.
Current flows through a capacitor because as the capacitor charges and discharges, electrons are constantly moving between the two plates. This movement of electrons is what we refer to as current.
A capacitor plays a variety of roles in a circuit depending on its configuration. It can block direct current (DC) while allowing alternating current (AC) to pass through, it can smooth out fluctuations in a voltage signal, and it can store electrical energy to be released later.
The size of a capacitor, specifically its capacitance, determines how much energy it can store and how quickly it can charge and discharge. A larger capacitor will have a higher capacitance and will be able to store more energy, but it will also take longer to charge and discharge compared to a smaller capacitor.