What is a Tesla coil?
A Tesla coil is an electrical resonant transformer circuit designed by inventor Nikola Tesla in 1891. It is used to produce high-voltage, low-current, high frequency alternating-current electricity. The first system that could wirelessly transmit electricity was, the Tesla coil it was a truly revolutionary invention. Early radio antennas and telegraphy used the invention, but variations of the coil can also do things that are just plain cool — like shoot lightning bolts, send electric currents through the body and create electron winds.
How does a Tesla coil work?
Employing copper wire and glass bottles, an amateur electrician can build a Tesla coil that can produce a quarter of a million volts. Tesla coils work by using resonance across a transformer to produce the very high voltage alternating current. A Tesla coil consists of two parts: a primary coil and secondary coil, each with its own capacitor. (Capacitors store electrical energy just like batteries.) The two coils and capacitors are connected by a spark gap — a gap of air between two electrodes that generates the spark of electricity. An outside source hooked up to a transformer powers the whole system. Essentially, the Tesla coil is two open electric circuits connected to a spark gap. A Tesla coil needs a high-voltage power source. A regular power source fed through a transformer can produce a current with the necessary power (at least thousands of volts). In this case, a transformer can convert the low voltage of main power into the high voltage. The power source is hooked up to the primary coil. The primary coil's capacitor acts like a sponge and soaks up the charge. The primary coil itself must be able to withstand the massive charge and huge surges of current, so the coil is usually made out of copper, a good conductor of electricity. Eventually, the capacitor builds up so much charge that it breaks down the air resistance in the spark gap. Then, similar to squeezing out a soaked sponge, the current flows out of the capacitor down the primary coil and creates a magnetic field. The massive amount of energy makes the magnetic field collapse quickly, and generates an electric current in the secondary coil. The voltage zipping through the air between the two coils creates sparks in the spark gap. The energy sloshes back and forth between the two coils several hundred times per second, and builds up in the secondary coil and capacitor. Eventually, the charge in the secondary capacitor gets so high that it breaks free in a spectacular burst of electric current. The resulting high-frequency voltage can illuminate fluorescent bulbs several feet away with no electrical wire connection. The principle behind the Tesla coil is to achieve a phenomenon called resonance. This happens when the primary coil shoots the current into the secondary coil at just the right time to maximize the energy transferred into the secondary coil. Think of it as timing when to push someone on a swing in order to make it go as high as possible.
What are its advantages?
Tesla Coil can produce high voltage alternating current at both high and low frequency. This high-frequency current can be transmitted wirelessly through the air to another receiver over a long distance without any adverse effects on the human body.
What are its disadvantages?
It's deeply inefficient. The transmitting antenna and the receiving antenna must be precisely tuned to each other, any deviation from this precise tuning results in an exponential loss of transmitting efficiency. It's impractical. The magnetic field generated by such a device would cause all sorts of noise in any unshielded electronic device. The cost of such a system would be immense, and the cost for powering it would be exponentially more than a direct power line. By Vishal Patil A highly experienced Mechanical Engineer