Download Ohms law working principle

Our aim is to make an automatic robot
that can follow a white lined path
placed over a black background. If
the robot goes out of track then it
senses the black region and returns to
the white line.
The robot consists of 2 light detecting sensors
paired with led s. We know that white color reflects
the light very well and the black surface doesn’t
reflect any light. The light emitted by the led s is
reflected is reflected back to the light sensors and
the robot moves forward. If the sensors come to the
black region no light is reflected from the led s so
the robot stops immediately.
IC7805 REGULATOR (9V-5V)
LM324N COMPARATOR
ULN2003 AMPLIFIER
LDR (LIGHT SENSORS)
LED
POTENTIOMETER 10KΏ
4 PIN CONNECTOR
CARBON RESISTANCE OF 10KΏ
CARBON RESISTANCE OF 100Ώ
This technology can be used for preventing an
automobile from getting on to the off road by
controlling the electronic breaks present in the
vehicles preventing it from a great accident.
This circuit should be placed in the middle of the
breaks and supply.
The only investment is to paint the roads with white
near the medians and at extreme left of the roads.
So if a car get on to this white region the breaks
gets operated preventing a great accident
The only defect is this technology cannot be
implemented during rain as the black region also
starts reflecting light.
This technology is the key for future generation
where cars don’t have steering wheel and only has
accelerators and breaks.
WIRELESS
ELECTRIC POWER
TRANSMISSION
MAGNETIC INDUCTION
WIRELESS TRANSMISSION OF
CURRENT IS BASED ON THE
ELECTRO MAGNETIC
INDUCTION.
INTRODUCTION
•Nikola Tesla was the first person to work on this
concept.
•This is based on the Faradays law of electromagnetic
induction.
•The faraday’s law states that when a coil of wire cut a
magnetic field or when the magnetic field cuts the coil
of wire, current is induced in the wire.
•In the case of a D.C current the magnetic field
created is constant and so the magnetic field
should be interrupted as to make a difference
in potential in the coil.
•Whereas in A.C current the magnetic field
generated is varying and this varying magnetic
field creates an e.m.f in the coil without any
movement in the coil.
•Hence A.C current can be used for the
transmission of the current.
•With A.C, a magnetic field is generated and is
used to transmit electricity without any
physical contact or connecting each other with
wires.
COMPONENTS
•Resistor ()
•Capacitor
•Transistor
•L.E.D
•Copper Coil
•Connecting wire
•The D.C current is first converted to A.C current.
•The converted current is then passed through a coil (primary coil) of wire
to create a varying magnetic field.
•So when a coil of copper wire is brought on the track of this magnetic field
the copper coil (secondary coil) gains a potential difference.
•And finally the A.C current is used in the circuit to light up an L.E.D.
•The A.C current is a varying current which changes its polarities.
•But it will not make any difference as the L.E.D blinks so fast that we
would not be able to identify the difference and we may get a constant
glow.
•Where as in the case a D.C current the current flowing is constant and the
bulb or an L.E.D will glow constantly.
µ-permeability of free
space
In the case of a straight wire the direction of
magnetic lines of force can be found out by
placing the thumb of right hand along the
direction of current. The direction of magnetic
lines is along the direction of our other fingers.
But in the case of a coil of wire it contains nloops.
In the case of a loop it contains minute straight
lines.
So the resultant direction is different in the case
of a loop.
The direction of magnetic lines of force in the
case of a loop can be determined by placing all
the fingers except the thumb along the direction
of current and the thumb must be kept
perpendicular to the other fingers as shown in
the figure. Then the thumb gives the directions of
the magnetic lines of force.
 Generating
power by placing satellites with
giant solar arrays in Geosynchronous Earth
Orbit and transmitting the power as
microwaves to the earth known as Solar
Power Satellites (SPS) is the largest
application of WPT. Another application of
WPT is moving targets such as fuel free
airplanes, fuel free electric vehicles, moving
robots and fuel free rockets. The other
applications of WPT are Ubiquitous Power
Source (or) Wireless Power Source, Wireless
sensors and RF Power Adaptive Rectifying
Circuits (PARC).
•This technology is
being
used
in
charging
mobile
phones.
•This can be used in
connecting networks
which are situated in
places
that
are
impossible
to
connect to.





This is a hand testing game to see how shaky
one’s hand is.
The principle of the game is very simple ! .
There is a maze over which one has to move a
circular loop.
If the hand is shaky then loop touches the maze
and there is a sound showing that you have
failed in the game.
If the hand is not shaky then one can bring the
loop from the start to end of the maze






The circuit consist of a led, 470Ω resistor, a 9V
battery , a switch and a buzzer.
The positive of the battery is connected to the
led ‘s anode through a current limiting resistor.
The negative of the battery is connected to the
maze .
The cathode of the led is connected to the loop
through a switch.
A buzzer is also connected to make the game
more interesting.
Whenever the loop touches the maze the circuit
is completed and the led and buzzer gets supply
at the same time and the user loses his chance.



Ohms law states that the potential
difference across two points is directly
proportional to the current flowing
through the two points or in other words,
the ratio of the voltage to current is a
constant.
That is when the resistance in between
the two points increases the current
flowing through the two points decreases
to maintain the same potential difference.
Similarly when the resistance in between
the two points decreases the current
flowing through the two points increases
to maintain the same potential difference.





This is the demonstration of the Ohms law.
A led and a buzzer are connected to a
variable resistor.
Changing the resistance changes the
current passing through the led and buzzer.
The circuit consists of a led, pot , buzzer,
a 470 Ω resistor, a variable resistor – 10 K
Ω pot and a buzzer.
The Ohms law is demonstrated by
varying the potentiometer.


When the resistance of the pot is at 0K the
resistance is very low and therefore maximum
current flows in the circuit and the led gives its
maximum light and buzzer its maximum
sound.
When the resistance of the pot is at 10K the
resistance is very high and therefore a very low
current flows in the circuit and the led gives its
minimum light and buzzer its minimum sound.
 In an intermediate position the led glows
according to the available current.


This can be shown by varying the pot in
one direction and the led dims gradually
and in the other direction it brightens up
gradually. Similarly the buzzer sound is
also increased in one direction and
decreased in the other direction.
This is a simple and effective
demonstration of Ohms law which every
one can understand easily.
•
•
•
Infra red sensor is a circuit which enables us to
detect infra red leakage in nuclear power plants.
Here is a basic model which can detect ir
radiations even if the source is quite far.
The circuit consists of an stop 1738,ne555,led
and some wires and capacitors of value less than
1uf.