1. Review: Ohm’s Law Formulas
There are three forms of Ohm’s Law:
V = IR
I = V/R
R = V/I
where:
V = Voltage
I = Current
R = Resistance
Fig. 3-4: A circle diagram to help in memorizing the Ohm’s Law formulas V = IR, I = V/R, and R= V/I. The V is always at the top.
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2. Series and Parallel Connections
Serial connection
Parallel connection

3. Series and Parallel
Series: Two or more elements are in series if they are cascaded or connected sequentially and consequently carry the same current.
Parallel: Two or more elements are in parallel if they are connected to the same two nodes and consequently have the same voltage across them.

4. Learning objectives
AC voltage source
Capacitors

5. Direct current and alternating current
A direct current (dc) remains constant (both in direction and magnitude) with time.
+ ve
An alternating current (ac) varies sinusoid ally with time.
- ve

6. Courtesy: http://gifsoup.com/view/4597630/ac-dc-current.html

7. AC Source Symbols

8. Learning objectives
AC voltage source
Capacitors

9. How Charge Is Stored in the Dielectric
A capacitor consists of two conductors separated by a dielectric (insulator).
Capacitors store energy in the electric field.
Storage means the charge remains after the voltage source is disconnected.
The measure of how much charge is stored is the capacitance C.
Fig. 16-1: Capacitance stores the charge in the dielectric between two conductors. (a) Structure.

10. The Farad Unit of Capacitance
Capacitance C is a measure of capacitor in storing electric charge under voltage.
The farad (F) is the basic unit of capacitance C.
One farad of capacitance C equals one coulomb of charge stored in the dielectric with one volt applied.
C=Q/V
Most capacitors have capacitance values less than 1 F:
C = 1 μF (microfarad) = 1 × 10-6 F
C = 1 nF (nanofarad) = 1 × 10-9 F
C = 1 pF (picofarad) = 1 × F

11. Capacitor Symbol