You can now see that as you plug in
more and more appliances, lamps, or other
electrical loads, the current increases. If cur-
rent increases, with the voltage at a fixed
value (approximately 110 volts), the
wattage consumed by these loads is also
increased. In this way, your electrical bill
also increases. In order to conserve energy
and save money, always turn off any
unnecessary load, be it the radio, television,
or light.
Refer again to the Project 1—Experimenter
in Chapter 19 of this textbook. In Problem 4,
the lights are connected in parallel. Each
light burns at the same brilliance as the
single light of Problem 2. Because the cir-
cuit is a parallel circuit, each light decreases
the total resistance of the circuit. The cur-
rent, of course, will increase (Ohm’s law).
Quiz—Chapter 7
Write your answers to these questions on a
separate sheet of paper. Do not write in this
book.
1. Write the formula for total resistance
when all resistors in a parallel circuit
are equal.
RT = ______.
2. Write the formula for total resistance of
two unequal resistors in parallel.
RT = ______.
3. Write the formula for total resistance of
three unequal resistors in parallel.
RT
= ______.
4. The sum of the branch currents in a
parallel circuit is equal to the ______ of
the circuit.
5. The voltage across all branches of a
parallel circuit is ______.
6. Conductance has the letter symbol
____ and is measured in ____. It is the
____ of resistance.
7. What is the conductance of a circuit
that has ten ohms resistance?
8. Find:
RT
= ______
IT = ______
IR1= ______
IR2= ______
9. Find:
RT
= ______
IT = ______
IR1= ______
IR2= ______
Chapter 7 Parallel Circuits
63
R1
50 Ω
R2
50 Ω
100 V
R1
300 Ω
R2
600 Ω
200 V
http://www.electronic-circuits-diagrams.com/
The Electronics Zone contains free
electronic circuit diagrams with a complete
explanation of how the circuit works.
Students and hobbyists enjoy reviewing
the wide range of circuits listed on this
site, as well as reading the free tutorials in
basic electronics.
Web Wanderings!