**27
October 2000**

**TERMINAL
DETAILS**

__General:__**
The Terminal provides the capacitance for the Secondary Circuit
making it resonant to a particular frequency (117kHz in our case).
It can range from about 10 to 100pF and more depending on its
physical shape and size. Tesla Coilers usually use either
spherical or toroidal shaped Terminals. They need to be made of
some kind of metal such as aluminium or copper and should be
smooth without sharp points. **

**Spherical
and Toroidal Terminal Formulas for capacitance:**

**Terminal
Voltages:**

**There are
two types of voltage specifications: Potential (V) and Electric
Field (E) Volts per metre. The Potential on any terminal is a
function of the electrostatic energy it contains and its
capacitance. The energy (joules) comes from the primary circuit,
and the capacitance is as determined above.This seems to be where
the laws of physics regarding conservation of energy and some
Coilers part company. One does not get millions of Volts out of a
terminal, but 100's of thousands. On the other hand, one can get
in excess of a million Volts per metre field intensity at the
surface of a terminal.This is where the terminal ionizes the air
about it and the charges break free to make those lovely sparks.**

**Case in
Point:**

**The
primary circuit has a 0.05uF capacitor and a 10kV rms Neon sign
transformer****.**** At the instant of
spark gap firing the capacitor has about 12kV charge (14.14kV
peak voltage available). Using the formula below, the energy in
the capacitor available for transfer to the Terminal via the
coils is 3.6 Joules.**

**Even
assuming no losses and the terminal capacitance is 50pF, the
Terminal Voltage potential works out to 379kV using the same
formula above manipulated to make Voltage the dependent variable.
By doing the following, a much easier formula for determining
Terminal Voltage is produced: **

**Remember,
there are circuit and radiation losses, so the actual Terminal
Voltage Vs will be somewhat less than the 379kV calculated.**