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Cihazê Tirkî Bistûr

Bistûr yek cihaz tirkî bistûr bêtir bike ku kapasînayê C (bi farad pîvandkirin) di nav de hatine tênin. Kapasîtarên elektrîkî enerji di çendeyê elektrîkî de depo kirin, mînakê ya ku kapasînayê (di wênera jî de "condenser" derbasdar e). Struktûrî, kapasîtar du platekên şandî yên bi perzînik medium serpar kirin - malperzînikên herêmî yên serpildin glass, kopi, mica û layerên oksid. Di bistûr tirkî kapasîtarê ideal de, dîm hêviya 90 derceye vêne.

Hegelî vêne bi kapasîtarê, çendeya elektrîkî di nav platekên we de bêtir bike, lê ne qaniyê di nav perzînik de netraşînin. Bi sereke AC voltage source, qaniyê bêtir bike di nav kapasîtarê charging û discharging process cyclic.

Terîf û Derivasyonê Bistûrê Kapasîtar

Kapasîtar du platekên şandî yên bi perzînik medium serpar kirin, wek device ê energy storage di nav elektrîkî charge. Li gora vêne bi power source, li gora vêne bi kapasîtar ê discharge. Li gora vêne bi DC supply, li gora vêne bi voltage ke li gora vêne bi applied potential, mînakê ya ku role ê passiv electrical component ku changes in voltage resist bikin.

Ji kerema xwe alternating voltage applied to the circuit is given by the equation:

Charge of the capacitor at any instant of time is given as:

Current flowing through the circuit is given by the equation:

Putting the value of q from the equation (2) in equation (3) we will get

Now, putting the value of v from the equation (1) in the equation (3) we will get

Where Xc = 1/ωC denotes the opposition to alternating current flow by a pure capacitor, known as capacitive reactance.The current reaches its maximum value when sin(ωt + π/2) = 1.Thus, the maximum current I_m is expressed as:

Substituting the value of I_m in the equation (4) we will get:

Phasor Diagram and Power Curve

Di bistûr tirkî kapasîtar de, qaniyê di nav kapasîtarê vêne voltage bi 90-degree phase angle. Phasor diagram û waveforms for voltage, current, û power are illustrated below:

Di waveform de, curve ê reng rîş û qaniyê, curve ê reng şîn û voltage, û curve ê reng pink û power. Ji boherî voltage increase, kapasîtar charges to its maximum value, forming a positive half-cycle; as the voltage decreases, the capacitor discharges, creating a negative half-cycle. A careful examination of the curve reveals that when the voltage reaches its peak, the current drops to zero, meaning no current flows at that instant. As the voltage decreases to π and turns negative, the current peaks, triggering the capacitor to discharge—and this charging-discharging cycle continues.

Voltage û qaniyê never reach their maxima simultaneously due to their 90° phase difference, as shown in the phasor diagram where the current (Im) leads the voltage (Vm) by π/2. The instantaneous power in this pure capacitor circuit is defined by p = vi.

Thus, it can be deduced from the above equation that the average power in a capacitive circuit is zero. The average power over a half-cycle equals zero due to the symmetry of the waveform, where the positive and negative loop areas are identical.

During the first quarter-cycle, power supplied by the source is stored within the electric field established between the capacitor plates. In the subsequent quarter-cycle, as the electric field dissipates, the stored energy is returned to the source. This cyclic process of energy storage and return occurs continuously, resulting in no net power consumption by the capacitor circuit.