Question

1) What are a Vande Graaf generator and a Tesla Coil? Why aren’t people hurt when they come in contact with such high voltage?

2) What is the difference between AC and DC? Three prong and two prong plugs? 110 and 220 plugs?

Answer 1

1. A Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column, creating very high electric potentials. It produces very high voltage direct current (DC) electricity at low current levels. It was invented by American physicist Robert J. Van de Graaffin 1929. The potential difference achieved by modern Van de Graaff generators can be as much as 5 megavolts.

The Van de Graaff generator was developed as a particle accelerator for physics research, its high potential is used to accelerate subatomic particles to great speeds in an evacuated tube. It was the most powerful type of accelerator of the 1930s until the cyclotron was developed. Van de Graaff generators are still used as accelerators to generate energetic particle and x-ray beams for nuclear research and nuclear medicine.

A Tesla coil is a radio frequency oscillator that drives an air-core double-tuned resonant transformer to produce high voltages at low currents.^{[10][15][16][17][18][19]} Tesla's original circuits as well as most modern coils use a simple spark gap to excite oscillations in the tuned transformer. More sophisticated designs use transistor or thyristor^[15] switches or vacuum tube electronic oscillators to drive the resonant transformer.

Tesla coils can produce output voltages from 50 kilovolts to several million volts for large coils. The alternating current output is in the low radio frequency range, usually between 50 kHz and 1 MHz. Although some oscillator-driven coils generate a continuous alternating current, most Tesla coils have a pulsed output; the high voltage consists of a rapid string of pulses of radio frequency alternating current.

People do not get hurt because net charge is very small and resistance of human body is very large. Current produced in these is not significant when body comes in contact.