©2011 - v 1/09 615-4665 (10-205) Tesla Coil Instructions and Applications Science First® would like to thank Robert Lichtenberg of Sugar City, Idaho for invalu- able technical assistance with these instructions. SCIENCE FIRST® | 86475 Gene Lasserre Blvd., Yulee, FL 32097 | 800-875-3214 | www.sciencefirst.com | [email protected] SCIENCE FIRST® | 86475 Gene Lasserre Blvd., Yulee, FL 32097 | 800-875-3214 | www.sciencefirst.com | [email protected] ©2011 - v 1/09 Warranty/Replacement Parts: Ball Terminal We replace all defective parts free of charge. Additional replacement Corona Cap parts may be ordered by referring to part numbers above. We accept Long Master Card, Visa, American Express Wire and purcahse orders from educational institutions in good standing. All products warranted to be free from Secondary defect for 90 days. Does not apply to accident, misuse or normal wear and Primary tear. Terminal Post Introduction: The Tesla Coil is an air-core Primary Capacitor trans former with primary and sec- Spark Gap ondary coils tuned to resonate. The primary and secondary function as a step-up transformer which converts Vibrator relatively low-voltage high current Knob to high-voltage low current at high Cord frequencies. Diagram 1 The Tesla Coil demonstrates the fundamental principles of high frequen cy electrical phenomena. It The capacitors are two large cyl- and closes when the magnetic field shows the principles of ionization of inders on either side of the spark gap. decays. This occurs 120 times per gases and behavior of insulators and They are high voltage capacitors of a second - each time the AC current conductors when in contact with high predetermined size and value. changes polarity of the electromag- frequency electrical fields. The primary coil is a pair of thick net. Its inventor, Nikola Tesla, con- insulated copper wires located next The capacitors charge up when ceived it to be a means to transmit to, but not touching, the second- the buzzer contacts are open, since electrical power without wires. An ary and connected in series with the the current passes into them to com- antenna would pull the transmitted capacitors and spark gap. plete the electrical circuit. When the electrical energy into the electrical The secondary is a cone-shaped contacts are closed, the capacitors system. You can also consider it a coil (cone-shaped to keep the coil are shorted together and current does simple radio transmitter. Operating compact and for manufacturing rea- not pass into them. The open contacts within a broad range of high fre- sons as less wire is needed) consisting allow the air in the spark gap -the quencies, which transmits power of 400 turns of thin enameled copper small space between open contacts rather than information. wire. It functions as a transformer to ionize, which permits a discharge by stepping up voltage to high levels. that short circuits the transformer and Components: The high voltage is given off by the capacitors. But the capacitors retain The Tesla Coil consists of a vibra- terminal. their electric charge, since the func- tor or transformer, two high voltage tion of a capacitor is to store an elec- capacitors, a primary, and a second- trical charge and thus provide energy’ ary connected to a ball terminal or How a Tesla Coil Works: to cre ate an electromagnetic field. antenna. Refer to Diagram 2. When the This spark taking place in this The vibrator is composed of an plug is inserted into 110 AC current spark gap does not consist simply of air slot core around which coils of (220 volt for #10-206), electricity a single spark passing in one direc- copper are wound; and a buzzer flows through the vibrator, an iron tion, as would appear to the eye, but which consists of two tungsten points core with hollow center wound a number of separate sparks passing or contacts which open and close by with coils of copper wire. This core back and forth in opposite directions. means of a spring as alternating cur- becomes an electromagnet. The buzz- They take place so rapidly you cannot rent and electricity passes through the er, 2 tungsten contacts opposite each see the direction change. The time core and discharges in the spark gap. other, not quite touching, pulls apart during which the spark appears to when the electromagnet is activated SCIENCE FIRST® | 86475 Gene Lasserre Blvd., Yulee, FL 32097 | 800-875-3214 | www.sciencefirst.com | [email protected] SCIENCE FIRST® | 86475 Gene Lasserre Blvd., Yulee, FL 32097 | 800-875-3214 | www.sciencefirst.com | [email protected] ©2011 - v 1/09 “ring” at the chosen high frequency . Primary Resonance: 1 µ H at .025 µ F Ball Termi- Resonance may also be compared nal 1 Primary, L = 1 µ H 2 π LC to a swing. When inductive imped- or 1 x 10-6 H F = 1.07 MHz ance and capacitive impedance of a circuit are equal, the electricity .05 µF 1600 E oscillates back and forth between inductive component (primary) and Buzzer Spark Gap capacitive component (capacitors, 2 Spring also called condensers). When push- Secondary, 90 pF at ing a swing, a person can cause large Capacitors, Total 50,000 E forward and backward motions with .025 f at 3000 E µ Iron Core Grounded Plug small pushes administered at the correct frequency. Applying energy at correct frequencies builds up high µ L2 = 277.77 H potentials in a resonant circuit. G =90 pF A person in a swing weighing 200 AC Choke Drive pounds may be pushed by a small Diagram 2 Tesla Coil 1/4 Wave child about 50 pounds who may push with only one pound of force. If he pass may only be a fraction of a sec- from the 60 cycle component of the times his pushes to coincide with ond, but during that time the current current, the electrical circuit will not the direction of the swing and keeps may have oscillated back and forth be complete in regard to the 60 cycle adding a pound of force each time, he several thousand times. component and you will not receive will eventually have to stop to avoid The electromagnetic field is a shock if you touch the coil directly . hurling the person in the swing out formed by the primary which Another safety feature is the fact that into space. converts the charge stored in the an air-core transformer by its nature An analogy used by inventor capacitors to magnetic energy. The does not pass 60 cycle current well. Nikola Tesla himself is to picture a electrical charge is trans ferred to the wine glass broken by a violinist’s primary by the capacitors when the note. The glass is shattered because magnetic field in the iron core decays. The result is that high frequency the vibrations happen to be the same When the magnetic field in the iron electrical energy is built up by the frequency as the vibrations of the core is reactivated, the field generated gener ation and decay of the magnetic glass. in the primary is the one to decay, field in the primary every halfcycle, Since at the right resonant and the electrical charge is transferred often reaching many million cycles frequen cy, the AC resistance, or back to the capacitors with every per second. reactive impedance, is zero with the half cycle, a charge of increasingly When the high frequency is great right coil and capacitor, and now the higher voltage as each activation of enough and reaches the voltage maximum current can flow according the magnetic field adds to the charges predetermined by the size and value to formula: 1 previously generated. of the capacitor , the primary induc- π The vibrator also acts as an air es a magnetic field in the secondary. 1/2 LC = Fr core transformer, boosting the voltage Inducing means a moving magnetic The secondary, like the vibrator, to medium high levels with every field causes a magnetic field to form functions independently as a step- half-cycle pulse of AC current. The in anoth er wire coil located close to, up transformer of about 3,000 volts. high frequencies produced are rich or inside, the first coil. Since it has many more coil turns of in harmonics since each pulse of The primary consists of two thick copper wire in its secondary from electricity across the spark gap is insulated copper wires which are the primary voltage of 110 volts of composed of many surges of electri- reso nated by the capacitors to equal AC input, then electrical energy is cal energy. the natural resonant frequency of supplied. The capacitors in this Coil have a the second ary. When the resonance As the electrical energy from the particular size and value. They serve equals that of the secondary, a mag- vibrator is fed to the capacitors of the the dual function of storing electric netic field is formed in the secondary. primary air core transformer and coil charge and filtering through the high Resonance may be compared to a at its base, it now creates another in- frequency component of electrical cymbal: when a cymbal of a certain dependent circuit of the vibrator type current while blocking low frequency size and weight is struck, it rings at a transformer. The vibrator secondary 60 cycle current. This is a safety specific frequency. In the Tesla Coil, output of 3,000 v is applied to this feature, since by isolating the primary the right capacitors and secondary primary circuit, known as the air core SCIENCE FIRST® | 86475 Gene Lasserre Blvd., Yulee, FL 32097 | 800-875-3214 | www.sciencefirst.com | [email protected] SCIENCE FIRST® | 86475 Gene Lasserre Blvd., Yulee, FL 32097 | 800-875-3214 | www.sciencefirst.com | [email protected] ©2011 - v 1/09 How To Operate: stranded wire.