Data Sheet

About Electricity (Mathematics)
13. Ohm’s Law
Ohms Law states that Voltage equals Current multiplied by
Resistance. If V = Voltage, I = Current, and R = Resistance,
then mathematically Ohms Law is V = I x R where “x” stands
for “multiplied by”. Since the law starts with Voltage, we need
a voltage source or a Power Supply. There are both DC (direct
current) and AC (alternating current) power supplies. Batteries
are also a source of DC
voltage. Using Algebra, any
one unknown can be calculated
if the other two variables are
known. For example, if V=9
Volts and R=1000 Ohms, then
I=0.009 Amp or 9 milliamps.
14. Switches and Power
A switch is a device that may control other components in
the circuit. It is used for power connection and disconnection.
A switch is a device that is either ON or OFF and used often
in digital electronics. Power is the product of the current in a
device multiplied by the voltage across it. Electronic Power is
expressed in Watts. Mathematically this
is expressed as W = V x I. If you have a
60 Watt light that is on a voltage of 120
Volts, then the current can be calculated
to be 60 Watts divided by 120 Volts,
which equals 1/2 Amp. Some switches
are controlled by magnets and others by
temperature.
15. Using Mathematics to Calculate Fuses
Many different appliances can be connected to draw current from
the outlets in your homes. If these outlets are all connected to
one fuse, then the fuse must
be able to handle the sum of
all the currents being drawn.
Fuses are used in the battery
holder that comes with this
product. Each current drawn
from any outlet in your home
will add up as the appliances
are turned ON because they
are all connected in parallel.
16. Calculating Resistance
Conductive paths are used to connect circuits and transfer
electricity. If the voltage on one end of the conductor is lower than
on the other end when current is owing, then the conductor
has resistance. The voltage drop on the conductor divided by
the current in the conductor is the Resistance of the conductor
or wire. In Mathematical
terms and from Ohms law,
this would be stated as
R = V ÷ I. If the voltage drop
is 2 Volts when 4 Amps is
owing, then the resistance
of the conductor is 1/2
Ohm.
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