Ohm's Law
V=IR
This is the most
fundamental
of the electrical-related equations. V stands for VOLTS. I
is for current in AMPS. R is for resistance in OHMS.
Coulomb's Law
F=8.9875x109((Q1Q2)/R2)
This is the most
fundamental
of the electrical-field related equations. F is the force
in Newtons. Q1 and Q2 are
the
individual charge particles (charges in units of coulombs).
R
is the radius between the two charges in meters. If one and only
one of the charges is negative, then the force will be
negative,
meaning that the charges are being pulled toward eachother.
Please
note that one electron or proton has a charge of 1.6021917
x
10-19 coulombs (electrons having a negative value).
Simple Electrical Field
E=8.9875x109((Q)/R2
This is a simple electrical-field related equation when one charge
ispresent.
E is the electric field in Newtons per coulomb. Q1
and Q2 are the individual charge particles (charges
in
units of coulombs). R is the radius between
the
two charges in meters. If one and only oneof the charges is
negative,
then the force will be negative, meaning that the charges are being
pulled
toward each other. Please note that oneelectron or
proton
has a charge of 1.6021917 x 10-19 coulombs (electrons having
a negative value).
Gauss's Law
F=E*A*COS(q)
Here is a fundamental equation describing Gauss's Law. F
is the "electric flux." E is electric field strength in
Newtons
per coulomb. A is the area in square meters. q
is the angle in which an field field penetrates.
Resistors in Series
RTotal=R1+R2+R3+...+RN
Here is a simple equation
that
adds up all the resistor values in a series configuration to give you a
total resistance in RTotal.
Resistors in Parallel
RTotal=1/(1/R1+1/R2+1/R3+...+1/RN)
Here is a simple equation
that
adds up all the resistor values in a parallel configuration to give you
a total resistance in RTotal.
Capacitors in Series
CTotal=1/(1/C1+1/C2+1/C3+...+1/CN)
Here is a simple equation
that
adds up all the capacitance values in a series configuration to give
you
a total capacitance in CTotal.
Capacitors in Parallel
CTotal=C1+C2+C3+...+CN
Here is a simple equation
that
adds up all the capacitance values in a parallel configuration to give
you a total capacitance in CTotal.
Batteries in Series
VTotal=VBattery1+VBattery2+VBattery3+...+VBatteryN
Using this simple equation,
you can get the total voltage of all the batteries connected in a
series
through VTotal. However, the maximum overall current
will
be equal or SLIGHTLY higher than that of the battery with the
LOWEST available current.
Batteries in Parallel
ITotal=IBattery1+IBattery2+IBattery3+...+IBatteryN
Using this simple equation,
you can get the total current of all the batteries connected in
parallel
through ITotal. However, the maximum overall voltage
will
be equal or SLIGHTLY higher than that of the battery with the
LOWEST voltage.
Simple Capacitance Formula
C=Q/V
Using this simple equation,
you can calculate a capacitor's value. C is the
capacitance
in farads. Q is the charge in coulombs. V
is
the voltage. Please note that the "wallop" from a capacitor is
directly
proportional to the voltage within it. BE CAREFUL when getting
into
those TV's, monitors, oscilloscopes, and the like. If you touch
the
wrong parts, the results can be a minimum of being thrown across a
room,
and the maximum could be a swift and painful death! Use care when
handling capacitors rated 500 mF or greater
and/or if the voltage is greater than about 30 volts. While
capacitors
at these values won't kill you, you can still get fried, but not well
done.
For capacitors at these values or smaller, you can discharge them
quickly
by shorting their ends together. For bigger capacitors, you
should
use a high-power resistor between the terminals, lest you want some 4th
of July in your shop! Even the capacitors used for powering an
electronic
flash on today's cameras can spark significantly AND carry a whopping
300
volts or more, as well as do a professional job of scaring the
daylights
out of you if you happen to short this sucker directly.
The Simple Capacitor
C=(8.8542 x 10-12 K A)/D
If a person were to make a
homemade parallel-plate capacitor, he or she can use this equation. C
is the capacitance in farads. K is the dielectric
constant
for the material (including air if nothing else is used) between the
plates.
A is the area of each plate (in square meters). D is the
distance between the plates in meters. Air has a dielectric
constant
of 1. At least most other substances have significantly higher
dielectric
constants, most of which range from around 3-6.
Amps / Coulomb Relationship
I=C/S
This equation simply shows
the relationship between current and the speed of electrons. I
is the current in amps. C is the number of coulombs. S
is the number of seconds.
Power
P=VI*COS(q)
Using this simple equation,
you can calculate the power consumed by a device. Unless you are
working with AC power at an angle other than 0 degrees, you can chop
off
the cosine portion of this equation and make life simple. P
is the power in watts. V is the voltage supplied. I
is the current (in amps) drawn by the device.
Power Through a Resistor
P=I2R
Or
P=V2/R
Using this simple equation,
you can calculate the power consumed by a resistor. P is
the
power in watts. R is the resistance in ohms. I
is the current (in amps) drawn by the device. When using the
second
equation, V is the voltage across the resistor.
Resistance of Wire
R=(rL)/A
This equation kind of shows
the quality of wire, particularly when lots of current most travel long
distances. R is the resistance in ohms. r
is
the "resistivity" in ohm-meters. L is the length of the
wire
in meters. A is the cross-sectional area of the wire in
square
meters. This equation partially shows why bigger wire is needed
for
devices that use more power.
Force Between Two Parallel Wires
F/L = (1.257 x 10-6 I1I2)/2pD
This equation gives the
force
between two parallel wires, both of which are carrying a
current.F
is the force in Newtons. L is the lengthof the wires in
meters.
Omit L if you want the TOTAL force. I1 and I2
are the currents in amps. D is the distance between the wires
in
meters.
Magnetic Force from Wire Carrying a Current
B=(1.257 x 10-6 I)/(2pR)
This equation gives the
magnetic
force induced by a wire carrying a current. I is
the
current in amps. R is the radius from the CENTER of the
wire
in meters. B is the magnetic field in units of tesla.
Magnetic Force from Object
Wrapped
with
Wire Carrying a Current (Wire
Having
Insulation)
B=(1.257 x 10-6 I
N)/L
This equation gives the
magnetic
force induced by a wire carrying a current. I is the
current
in amps. R is the radius from the CENTER of the wire in
meters.
B
is the magnetic field in units of tesla. N is the number
of
turns. L is a unit length in meters. To get the
entire
magnetic field, just omit the division by L and make life
simple.
Magnetic Flux
FB=B*A*COS(q)
Here is a fundamental
equation
describing calculating magnetic flux. FB
is the "magnetic flux." E is magnetic field strength in
tesla.
A
is the area in square meters. q
is the angle in which an field field penetrates.
Later on,
if
God allows, I may add future equations for RL, RC, and RLC circuits as
well as formulas related to diodes, complex power, and more.