BMW ONBOARD COMPUTER Bedienungsanleitung PDF herunterladen (Seite 25)

E46 Driver Information

E46 Convertible Third Brake light

The E46iC uses Neon technology for the third brake light which is mounted in the trunk lid.

The remainder of the exterior lighting circuits carry over from the E46 Sedan and

Coupes.The Electronic brake light switch is the input to the LSZ for brake light activation.

The LSZ, as an output, provides power to the Neon light module for activation of the light.

The light module consists of the ignitor, and Neon tube.

Neon Technology

Neon (symbol Ne) produces a glow in

a vacuum electric-discharge tube and is used extensively in the familiar advertising dis-

plays.

A neon light is a glass bulb or tube containing neon (gaseous element) at low pressure,

and two metallic electrodes. To make a neon light, the tube is bent while warmed, to the

desired shape and sealed at both ends. During the sealing process, electrodes are added

at each end. An access port is left near one end and a vacuum is applied to the interior

of the tube. After the air and humidity has been removed, the neon gas is added under

low pressure and the tube is sealed.

The light produces a reddish-orange glow when an electric current (applied across the

electrodes) is raised in voltage to the point at which it ionizes the gas in the tube. The

voltage at which the light glows varies with the design of the tube. When the glass tube is

ionized, the voltage drop across the tube is constant, regardless of the amount of current

flowing through the tube. The neon glows with an even intensity throughout the length of

the tube.

A variant of this is the glass tube containing ionized neon at very low pressure. The tube

shines with a brilliant red glow if a high-voltage alternating current is applied to the elec-

trodes sealed in the ends of the tube.

The use of neon lighting provides several advantages

to automobile manufacturers and consumers:

Light failures caused by shock and vibration are minimized,

because neon operates without a filament.

The average life of the light is considerably higher as

compared to incandescent bulbs.

Styling of the light includes a more uniform distribution of

light across the lens, and neon tubes can be bent to

conform to the contour of the vehicle.

Amber neon allows the use of a clear lens (for vehicle color

schemes).

Neon enhances safety because of the extremely fast igni-

tion time of the light (instantaneous braking signal), allowing

other drivers more time to react.

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BMW ONBOARD COMPUTER Bedienungsanleitung Seite 25