Noob to electronics. Quick question

[Focalr]

I tend to overthink and find simple concepts diffcult. I understand the charging of cap C1 in figure “A”. My question is in figure “B”. With the switch there, cap C1 discharges thru R2 back into + plate of C1. Why doesn’t current get pulled from battery thru R1 and R2 as well? Doesn’t it “see” the positive voltage on the + plate of C1?

Thanks for the help

 

[Tony Stewart]

No, the current loop was broken with the switch.

 

[rjenkinsgb]

One of the most basic principles is that the current in a series circuit is the same at all points.
It is a derivative of Ohms Law.

(There may be transient effects due to capacitance or "transmission line" effects when the current or voltage changes quickly, but that's not relevant for simple circuits such as yours. That's for such as RF or high speed logic etc).

Series and parallel circuits - Wikipedia

en.wikipedia.org

From that rule, as there can be no current at the battery positive due to S1 disconnecting it, there can be no current through the battery or R1.

 

[Diver300]

In the figures, the current is shown in the charging and discharging paths is in the opposite direction to the way it is normally shown. That convention will probably apply to the whole publication.

The convention of +ve and -ve was assigned before anyone knew about electrons, and so current is said to flow in the opposite direction that the negatively charged electrons flow. At some time, possibly the 1970s, and possibly mainly in America, the flow direction of the electrons was shown in some books, like in the figures in the first post. That idea was too late and never took on, and current flow is now almost always shown as +ve when it is flowing in the opposite direction to the electrons.

https://circuitglobe.com/electric-current.htm

 

[Focalr]

Thank you all for the replies.

 

[ZipZapOuch]

If current would have flowed through to R1, some parts of your circuit would have a mis-match in the number of electrons vs protons and a net electrostatic charge. Net electrostatic charges don't tend to happen so we can assume that electron flow stops to any part of the circuit that is not, in fact, a circuit (i.e. circuitus : "to go around").

 

[BR-549]

Charge can not be pulled or stuffed into a battery. A battery has to circulate charge. When charging a battery, charge is not installed. Charging a battery is just like winding a spring. Then the spring circulates the current thru the battery. Most cars use a 12 V spring.