Electricity - Capacitors

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Storing Electric Charge - CAPACITANCE

When there are two conductors separated in space (by vacuum or insulator), there is an electric field between them. As the process proceeds a POTENTIAL DIFFERENCE develops.

C=Q/V in FARADS (proportional to A/d)

Capacitance

- amount of charge separation that can be maintained for the given potential difference. Used in our nerve cells keeping K+ and Cl- conc

-ability to store energy (total work)

Graphically - TOTAL work done = area under the curve A=1/2bh

E(U)= Wtotal = 1/2Q^2/C = 1/2CV^2

Adding capacitors- basically the SAME as RESISTANCE

Capacitors in Parallel

Adding in parallel just increases AREA. thus capacitance increases in proportion to that.

C= C1 + C2 +C3

Capactiors in Series

1/C = 1/C1 + 1/C2

Summary

-Capacitor stores charge

-measured in F, Farad

-C = Q/V

-C=Er Eo A / d

-1/2CV^2 - energy stored

-can be series or parallel