Re: [T3] Coil Spark

["Drake ." <vw_type3@hotmail.com>]

<x-flowed>>Why/how is this possible? Wouldn't a setup like this
> fail?

A coil works by induction. There is a primary side of a coil and a secondary 
side, its essentially a transformer. The primary side is a giant coil of 
wire, one wire that runs from the + side to the - side on the coil. The 
secondary side is connected to the high voltage connection, the one that 
plugs into the dist cap.

The + side of the coil is connected to the battery (through the ignition 
switch) the - side is connected to ground, through the points. When the 
points are closed you provide a ground to the circuit allowing current to 
flow through the primary side of the coil. This current flow creates a 
magnetic field around the primary windings of the coil. This magnetic field 
likewise surrounds the secondary side of the coil which is intertwined with 
the primary side, though not electrically connected.

When the points open the curcuit is opened, as there is no longer a ground 
for current to flow. This causes the magnetic field to collapse rapidly, 
which induces a current flow in the secondary side of the coil....

current flow through a wire creates a magnetic field around the wire, a 
magnetic field moving across a wire creates current flow

....The induced current flow in the secondary travels out the coil through 
the cap and rotor across the air gap of the plug to ground.

The "coil" takes a small voltage, high current (relatively) and turns it 
into very high voltage but minimal current.


With your test light connected to the + side of the coil you are providing a 
ground via the test light which causes current to flow and lights the light. 
When you put a test light on the - side of the coil you are again providing 
a ground, but this time current is just flowing thorugh the length of wire 
that is in the primary side of the coil

Drake
72 square (stock)
63 bug (darkside)
San Jose, Ca.




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