A child on a swing is a good example of this. A swing is a type of mechanical resonance, so only when the child pumps her legs at the natural frequency of the swing is she able to impart substantial energy. Another example involves acoustic resonances: Imagine a room with 100 identical wine glasses, each filled with wine up to a different level, so they all have different resonant frequencies. If an opera singer sings a sufficiently loud single note inside the room, a glass of the corresponding frequency might accumulate sufficient energy to even explode, while not influencing the other glasses. While these considerations are universal, applying to all kinds of resonances (e.g., acoustic, mechanical, electromagnetic, etc.), the MIT team focused on one particular type: resonator is a device or system that exhibits resonance or resonant behavior, that is, it naturally oscillates at some frequencies, called its resonance frequencies, with greater amplitude than at others. Although its usage has broadened, the term usually refers to a physical object that oscillates at specific frequencies because its dimensions are an integral multiple of the wavelength at those frequencies. The oscillations or waves in a resonator can be either electromagnetic or mechanical. Resonators are used to either generate waves of specific frequencies or to select specific frequencies from a signal. Musical instruments use acoustic resonators that produce sound waves of specific tones.
In a theoretical analysis, they demonstrate that by sending electromagnetic waves around in a highly angular waveguide, evanescent waves are produced which carry no energy. If a proper resonant waveguide is brought near the transmitter, the evanescent waves can allow the energy to tunnel (specifically evanescent wave coupling, the electromagnetic equivalent of tunneling) to the power drawing waveguide, where they can be rectified into DC power. Since the electromagnetic waves would tunnel, they would not propagate through the air to be absorbed or dissipated, and would not disrupt electronic devices or cause physical injury like microwave or radio wave transmission might.
In order for the power transfer to be efficient, we design the system such that the rate of energy transfer between the emitter and the receiver is greater than the rate of energy dissipation. This way the device can capture the energy and use it for useful work before too much of it get wasted away.
Newspapers of the time labeled Wardenclyffe &quot;Tesla&apos;s million-dollar folly&quot;. In spite of this he had made numerous experiments of high quality to validate his claim of possibility of wireless transmission of electricity (Fig.2). But this was an unfortunate incidence that people of that century was not in a position to recognise his splendid work
1.OBVIOUS ADVANTAGE OF NO WIRES 2. the transmission and distribution losses are the main concern of the present power technology. Much of this power is wasted during transmission from power plant generators to the consumer. The resistance of the wire used in the electrical grid distribution system causes a loss of 26-30% of the energy generated. This loss implies that our present system of electrical distribution is only 70-74% efficient. 3. Need more light in your office, Simply place the lamp where ever you need it.
3. It is like Wi-Fi, someone can be using your internet or your power
Electromagnetic interference (or EMI, also called radio frequency interference or RFI) is an unwanted disturbance that affects an electrical circuit due to electromagnetic radiation emitted from an external source.  The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit. The source may be any object, artificial or natural, that carries rapidly changing electrical currents, such as an electrical circuit, the Sun or the Northern Lights. EMI can be induced intentionally for radio jamming, as in some forms of electronic warfare, or unintentionally, as a result of spurious emissions and responses, intermodulation products, and the like. It frequently affects the reception of AM radio in urban areas. It can also affect cell phone, FM radio and television reception, although to a lesser extent. EMI or RFI may be broadly categorized into two types; narrowband and broadband. Narrowband interference usually arises from intentional transmissions such as radio and TV stations, pager transmitters, cell phones, etc. Broadband interference usually comes from incidental radio frequency emitters. These include electric power transmission lines, electric motors, thermostats, bug zappers, etc. Anywhere electrical power is being turned off and on rapidly is a potential source. The spectra of these sources generally resembles that of synchrotron sources, stronger at low frequencies and diminishing at higher frequencies, though this noise is often modulated, or varied, by the creating device in some way. Included in this category are computers and other digital equipment as well as televisions. The rich harmonic content of these devices means that they can interfere over a very broad spectrum. Characteristic of broadband RFI is an inability to filter it effectively once it has entered the receiver chain.  
ppt by shubham singh kalhans on witricity
A Power point presentation
TOPICS TO BE DISCUSSED
2. BASIC PRINCIPLE
6. DEVELOPMENT OF WITRICITY
10.THE FUTURE ASPECTS
4. EXPERIMENTAL SETUP
WITRICITY is the transfer
of electricity from one place
to another without
WITRICITY is a
Combination of words for
Transmission of Electricity.
Allows power to cross
distances even when there is
no physical connection
between the power source
and the object to be
WHAT IS WITRICITY???
PRINCIPLE OF WIRELESS
TRASMISSION OF ELECTRICITY
Two resonant objects of the same resonant frequency
tend to exchange energy efficiently, while interacting
weakly with extraneous off-resonant objects
MAGNETICALLY COUPLED RESONATORS
The system involves two electromagnetic resonators
coupled through their magnetic fields.
This enabled efficient power transfer, even when the
distance between them was several times larger than the
sizes of the resonant objects.
How Wireless Electricity Works
The oscillating current inside the transmitting coil causes the
coil to emit a magnetic field.
A circuit A attached to the power supply supplies power to the
transmitting coil B.
The setup requires two identical coils with one coil connected
to a load,like a bulb.
The receiving coil C has the exact same dimensions as the
sending coil B and thus resonates at the same frequency and due
to a process called magnetic induction voltage is induced in coil
Thus,coil C picks up the energy of the coil B’s magnetic
The energy of the oscillating magnetic field induces an
electrical current in the receiving coil, lighting the bulb D.
We determine the efficiency of transfer of energy takingWe determine the efficiency of transfer of energy taking
place between the source coil and the load by measuring theplace between the source coil and the load by measuring the
current at the midpoint of the each coils with a currentcurrent at the midpoint of the each coils with a current
EFFICIENCY OF WITRICITY
Is WITRICITY an entirely new
Wireless power transmission is not a new
Dr.Nikola Tesla demonstrated a
"transmission of electrical energy without
wires" that depends upon electrical
conductivity as early as 1891.
The Tesla effect (named in honor of Tesla) is the term for
an application of the wireless movement of energy through
space and matter, not just the production of voltage across
Dr. Nikola Tesla shows us that he is indeed the “Father of
Starting in 1901, Tesla made
Wardenclyffe Tower Project for
wirelessly sending industrial
amounts of energy on large-scale.
“ Ere many generations pass, our
machinery will be driven by a power
obtainable at any point of the universe
He showed how power can be transferred through free space
INVENTOR OF WITRICITY
The experiment involving the discovery of WITRICITY
was led by MIT physics professor Marin Soljacic and
was reported on the June 7,2007.
From left to right: Soljacic, Karalis, and Joannopoulos,
with a figure from their paper in the background.
Say good bye to
ADVANTAGES OF WITRICITY
NO POWER CORDS
The electrical energy can be transmitted without wires, so
there will be no need of power cords.
LOW POWER LOSS
Due to absence of conventional wiring system,transmission
losses are very low.
PROVIDES EARTH FREE SUPPLY
Reduces chances of electric shock.
No need for external wiring so no need for electrician.
No meter rooms and electrical closets required.
NO TRANSFORMER NEEDED
It eliminates the need of Step Down Transformers.
LIMITATIONS OF WITRICITY
Retrofitting old equipment or purchasing new equipment
could become a very expensive endeavor.
Possibility of energy theft.
This technique can transmit electricity for short
Employed in cases where instantaneous and continuous
transfer of power is needed.
SCOPE OF WITRICITY
To overcome situations where normal cabling is difficult
or financially impractical
WITHIN NEXT 10 YEARS
Short distance induction
After 50 Years – Moderate distance Induction
After 100 Years – Long distance