Bee Midterms
Bee Midterms
Bee Midterms
ELECTRICAL
CIRCUITS
ELECTRICITY
► An interconnection of
electrical elements.
• Battery
• Lamp
• Connecting wires
CHARGE
R = ρL / A (Ω)
Resistance Varies with Temperature
POWER
5. An electric stove with four burners and an oven is used in preparing a meal as
follows:
► Burner 1: 20 minutes
► Burner 2: 40 minutes
► Burner 3 : 15 minutes
► Burner 4 : 45 minutes
► Oven : 30 minutes
If each burner is rated at 1.2kW and the oven at 1.8kW and the electric cost 12 cents
per kWH, calculate he cost of the electricity used in preparing the meal.
Calculate the equivalent resistance of the given circuit.
Calculate the equivalent resistance of the given circuit.
Determine the equivalent resistance between terminals a and b
Determine the equivalent resistance between terminals a and b
DELTA TO WYE
TRANSFORMATION
The Delta-Wye transformation is an extra technique
for transforming certain resistor combinations that cannot
be handled by the series and parallel equations.
Determine the equivalent resistance if cach resistance has a value 3 ohms.
Sample 2
Sample 1
KIRCHHOFF’S LAW
LEARNING OBJECTIVES
By the end of this section, you will be able to:
• State two Kirchhoff’s Law
• Analyze a complex circuit using Kirchhoff’s rules, using the
conventions for determining the correct signs of various
terms.
Kirchhoff's circuit laws are
two equalities that deal with
the current and potential
difference (commonly known as
voltage) in the electrical circuits.
They were first described in 1845
by German physicist Gustav
Kirchhoff. This generalized the
work of Georg Ohm and preceded
the work of James Clerk Maxwell.
they are also called Kirchhoff's
rules or simply Kirchhoff's laws.
The algebraic sum of all the voltages in a close loop circuit is equal to zero.
Determine the currents I1, I2, I3, I4, and I5 in the circuit shown below:
Determine the currents in the circuit shown below:
Determine the indicated currents in the given circuit below.
Calculate I1 to I9
Determine E if Vab is 6V
Determine E if Vab is equal to10V.
Determine E if Vab is equal to 6V.
THE BATTERY
Battery
Batteries are a collection of one or more cells whose chemical reactions create a
flow of electrons in a circuit. All batteries are made up of three basic
components: an anode (the '-' side), a cathode (the '+' side), and some kind of
electrolyte (a substance that chemically reacts with the anode and cathode)
When the anode and cathode of a battery is connected to a circuit, a chemical
reaction takes place between the anode and the electrolyte. This reaction causes
electrons to flow through the circuit and back into the cathode where another
chemical reaction takes place. When the material in the cathode or anode is
consumed or no longer able to be used in the reaction, the battery is unable to
produce electricity. At that point, your battery is "dead."
Batteries that must be thrown away after use are known as primary batteries.
Batteries that can be recharged are called secondary batteries.
Cell
When positive terminals of all cells are connected together and similarly negative
terminals of these cells are connected together in a battery, then the cells are said to be
connected in parallel. These combinations are also referred as parallel batteries. If
emf of each cell is identical, then the emf of the battery combined by n numbers of
cells connected in parallel, is equal to the emf of each cell.
Step-3 Now, in a circuit, only one independent energy source is present. You need to
find a response with only one energy source in the circuit.
Step-4 Repeat step-2 and 3 for all energy sources available in the network. If there
are three independent sources, you need to repeat these steps three times. And every
time you get some value of the response.
IL2 = 12A