Manual

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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