Download Engineering Review – Electric Circuits I

OHMS LAW
V = Voltage, I = Currect, R = Resistance of in a circuit
V=I*R
Power:
𝑽𝟐
𝑷𝒐𝒘𝒆𝒓 = 𝑰 ∗ 𝑽 =
= 𝑰𝟐 ∗ 𝑹
𝑹
RESISTORS
•
Combining resistances in series:
𝑹𝒆𝒒 = 𝑹𝟏 + 𝑹𝟐 … + 𝑹𝒏
•
Combining resistances in parallel:
𝑹𝒆𝒒 =
𝟏
𝟏
𝟏
𝟏
+
+⋯
𝑹𝟏 𝑹𝟐
𝑹𝒏
CAPACITORS
•
Combining capacitors in series:
•
𝑪𝒆𝒒 =
•
Combining capacitors in parallel:
𝑪𝒆𝒒 = 𝑪𝟏 + 𝑪𝟐 … + 𝑪𝒏
•
Charge on a capacitor:
𝟏
𝟏
𝟏
𝟏
+ +⋯
𝑪𝟏 𝑪𝟐
𝑪𝒏
Charge = Q =C*V
C = Capacitance, V = Voltage Across the capacitor
INDUCTORS
•
Inductors in series:
𝑳𝒆𝒒 = 𝑳𝟏 + 𝑳𝟐 + ⋯ 𝑳𝒏
•
Inductors in parrellel:
𝑳𝒆𝒒 =
𝟏
𝟏
𝟏
𝟏
+ +⋯
𝑳𝟏 𝑳𝟐
𝑳𝒏
KIRCHOFF’S CURRENT LAW (FOR NODES)
𝑰𝒊𝒏 =
•
𝑰𝒐𝒖𝒕
This can be applied to a node to determine the current in a leg of the other legs
are know, by summing the currents in and out of the node.
KIRCHOFF’S VOLTAGE LAW
𝑽𝒓𝒊𝒔𝒆𝒔 =
•
𝑽𝒅𝒓𝒐𝒑𝒔
This means that in any loop of a circuit, the sum of the voltage sources is equal to
the voltage drops caused by the loads.