Capacitor and diode curcit for ac to dc voltage

[nokia8650]

http://img42.imageshack.us/img42/2461/49889005.th.jpg

My question is, why does the dc voltage vary with time in this way? Ply it is something to do with the diode allowing current to flow when it has 0.7V or more across it, allowing the capacitor to charge, and when the voltage drops to below this, the capacitor discharges, however could someone please provide a more comprehensive explanation?

Thanks a lot in advance.

 

[berkeman]

http://img42.imageshack.us/img42/2461/49889005.th.jpg

My question is, why does the dc voltage vary with time in this way? Ply it is something to do with the diode allowing current to flow when it has 0.7V or more across it, allowing the capacitor to charge, and when the voltage drops to below this, the capacitor discharges, however could someone please provide a more comprehensive explanation?

Thanks a lot in advance.

Your explanation is correct. The droop between the power input part is at the RC time constant specified by the load R and the storage C.

 

[nlightner]

The circuit shown in the image is a simple rectifier circuit, which converts alternating current (AC) voltage to direct current (DC) voltage. The two main components in this circuit are the capacitor and the diode.

The AC voltage source is connected to the circuit through the diode, which acts as a one-way valve for electric current. When the AC voltage is positive, the diode allows current to flow through it and charges the capacitor. This charging process continues until the voltage across the capacitor reaches the peak value of the AC voltage.

However, when the AC voltage becomes negative, the diode blocks the current from flowing through it. At this point, the capacitor acts as a source of voltage, supplying the stored charge to the rest of the circuit. This results in a pulsating DC voltage, with the amplitude equal to the peak value of the AC voltage.

The reason for the variation of the DC voltage with time is due to the nature of the AC voltage. Since the AC voltage alternates between positive and negative values, the capacitor charges and discharges accordingly, resulting in a pulsating DC voltage. The amplitude of the DC voltage depends on the peak value of the AC voltage and the capacitance of the capacitor.

In summary, the capacitor and diode work together in this circuit to convert AC voltage to DC voltage by utilizing the properties of the diode as a one-way valve and the capacitor's ability to store and release electric charge.