Welcome back! This week and next, we’re spending some time with the ever-popular Tesla Coil, demonstration K7-61 in our demonstration index. You can see it in action in this video with graduate student Haotian Wang

A Tesla coil is a particular type of transformer circuit, a tuned or resonant transformer, that can produce very high voltages. While transformers are used in many applications in technology to transfer energy and convert to different voltages, a resonant transformer incorporates an inductor-capacitor combination, or LC circuit (from the traditional notation on circuit diagrams for inductors and capacitors), to both step up the voltage and to temporarily store energy, releasing it in dramatic bursts.

 Circuit diagram of a Tesla coil

This kind of induction device was historically used as part of early spark-gap radio systems. Today they are primarily used for research, education, and entertainment; although small Tesla coils also have applications for detecting minute changes in the conductivity of their surroundings, making them useful for testing vacuum seals in equipment.