# Question about capacitor charging/discharging in a continuous circuit

#### AltoInferno

Joined Oct 15, 2014
1
Hello, everyone!

So, I'm new to this particular website, and pretty much new to the concept of forum posting at all, so I apologize for any general mistakes on my part. That being said, I present my question!

So I have recently bee introduced to capacitors and their roles in circuits. I know that caps in parallel increase the total capacitance, while caps in series really just improve safety from shorts and fiddle with voltage (not very certain of that, perhaps a topic for me to read up on). What I'm not understanding is the method in which they are charged and then used in a circuit when they are needed.. I've been thinking about how capacitors can draw from a power source that touches the leads directly, and then discharge when the power source is removed from the leads. My question is, are there any other ways of charging to the capacitor in the circuit other than directly touching it with a power source, or putting the power source in parallel to the circuit? If not, what are some examples of how they are charged and discharged in a decent circuit?
Thanks!

#### MikeML

Joined Oct 2, 2009
5,444
Filter capacitor in a DC power supply. The capacitor is used to store energy which manifests as load current inbetween pulses from the rectifier.

#### crutschow

Joined Mar 14, 2008
34,407
You have to make a connection to both leads of a capacitor to either charge or discharge it.

#### wayneh

Joined Sep 9, 2010
17,498
Caps in a circuit are there for temporary charge storage, to change the pattern of flow over time. Charging comes from a peak voltage, which gets softened by the capacitor being there to absorb some charge at the peak. The capacitor returns the charge to the circuit when a voltage trough comes along.

An important feature of the capacitor's property is that, once charged, no more current can flow through it. So capacitors block DC current once they fill up. On the other hand, pulses of current that are small compared to the capacity of the capacitor pass through it as if it wasn't there. For instance an AC signal can be shorted to ground by placing a capacitor between the signal and ground. On a DC supply, such a capacitor is often used to filter out anything that isn't DC, i.e.. the noise in the DC.

#### Vinetou

Joined Sep 5, 2014
12

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