Handout Activity: HA802

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1 Lighting system HA802-2 Handout Activity: HA802 Lighting system The lighting system provides a means of allowing the driver to both see when driving in poor visibility conditions and to provide a means of signaling to other drivers. Lighting systems improve visibility at night, and make a vehicle visible to other road-users. A lighting switch operates tail-lights, park lights, and headlights to allow the driver to see ahead. A dip switch allows the driver to change the beams from high to low, or vice-versa, as required. Stop-lights operate when the brake pedal is depressed. Turn-signals alert other drivers of a change in direction, and are mounted so they can be seen from the front, rear and sides of the automobile. An emergency flasher system operates both front and rear turn-signals at the same time. Other circuits operate courtesy, or convenience lights, reversing lights, and fault indicators. 1. Turn-signals alert other drivers of a change in direction, and are mounted so they can be seen from the, rear and sides of the automobile. 2. A switch allows the driver to change the beams from high to low, or vice-versa, as required. 3. operate when the brake pedal is depressed. Score / Page 1

2 Light bulbs HA803-2 Handout Activity: HA803 Light bulbs Most lamps or light bulbs consist of a fine coil of tungsten wire, called a filament, enclosed in a clear glass envelope from which all air has been removed. Modern vehicles use many different kinds and sizes of lamps, also known in some places as light bulbs, or light globes. Incandescent lamps Incandescent lamps all consist of one or more filaments which heat up until they glow. The filament material doesn t burn because most of the air in the bulb has been replaced by inert gases that stop combustion occurring. The power in watts is often marked on the lamp. The power in watts being consumed by the lamp is found by multiplying the voltage to the lamp by the current flowing through it. Halogen lamps Halogen lamps are filled with a halogen gas such as bromine or iodine. These have a much longer life, and are generally brighter and produce more light per unit of power consumed, but they are very hot in use. They are consequently manufactured from highly heat resistant materials and the bulbs must be handled carefully because they are sensitive and can be damaged even by residue from fingerprints. Other lamp types Conventional incandescent lamps are being replaced in many applications by other more efficient types of lights, such as fluorescent lights, high-intensity discharge (HID) lights, and light-emitting diodes (LED) Page 1

3 Light bulbs HA Conventional incandescent lamps are being replaced in many applications by other more efficient types of lights, such as lights, high-intensity discharge (HID) lights, and light-emitting diodes (LED). 2. Halogen lamps are filled with a halogen gas such as or iodine. 3. Incandescent lamps all consist of one or more which heat up until they glow. Score / Page 2

4 Bulb information HA804-2 Handout Activity: HA804 Lamp/light bulb information All lamps or light bulbs have letters or numbers which indicate the power consumed by the bulb in operation and the nominal operating voltage. All lamps or light bulbs have letters and numbers stamped on them which indicate the power consumed by bulb operation at the nominal operating voltage. For instance, in a 12V / 21W bulb the filament will consume 21 watts of power when 12 volts is applied across the filament. While the wattage is not necessarily an indication of light output, it can be generally assumed that, for similar types of lamps, the higher the wattage the greater the light output will be. 1. For instance, in a 12V / 21W bulb the filament will consume 21 of power when 12 volts is applied across the filament. 2. All lamps or light/bulbs have letters and numbers stamped on the bulb which indicate the consumed by bulb operation at the nominal operating voltage. Score / Page 1

5 LED lighting HA805-2 Handout Activity: HA805 LED lighting Light Emitting Diodes, or LEDs, are being increasingly used in automotive lighting applications, because they operate instantly, are more reliable, and last longer. Light Emitting Diodes, or LEDs, have been used for some time in various automotive applications such as warning indicators and alphanumeric displays. More recent developments in LED technology have seen the production of a wider range of colors, and LEDs that are brighter than previous types. It is now possible to get bright red, green, blue, yellow and clear or white light LEDs. This has made it possible to use LEDs for many new applications, such as more general lighting applications. For example LEDs can now be used for stoplights, indicators and interior lighting on vehicles. One of the advantages of LEDs is that they turn on instantly. This is particularly useful in brake lights as they can reduce the braking response time by 2/10th of a second. This translates to an extra 16 feet or 5 meters of stopping distance at highway speeds. LEDs also have better visibility in poor weather and they can last up to 100 times longer, reducing the cost of servicing. LEDs can be specifically designed for LED lighting and also as LED replacement bulbs for more traditional bulb holders. For automotive applications a number of LEDs are grouped together to provide the amount of light required for the application. Additionally LED light lenses are specifically designed to get the most out of the available light. An LED is like a normal diode and only passes current flow in one direction. This means they are polarity conscious. When an LED is forward biased, current flows through it and it emits light. So it is essential that when the LED is coupled to an electricity supply, it must be done in the correct polarity in order for the lights to work. A typical LED has a voltage drop of 1.2 volts across it when it is forward biased and emitting light. When used in automotive lighting, many LEDs are required to give off the required amount of light. To do this they are usually connected in groups called series strings. A number of series strings are then connected in parallel until the necessary number of LEDs are connected to give off the required amount of light. LEDs work best when the voltage to them and the current flow through remains constant at a preset level. There are two main ways to achieve this; the first is via a resistor. The second and more preferred way is through the use of a voltage regulation circuit. Some LED lights are multi-voltage, this means they can work on both 12 and 24-volt systems. These are normally used in aftermarket products, which are able to be fitted to a wide range of vehicles Page 1

6 LED lighting HA Like a normal diode, it consists of a chip of semiconducting material impregnated, or doped, with impurities to create a structure called a. 2. When an electron meets a hole, it falls into a lower energy level, and releases in the form of a photon as it does so. 3. An LED is a special type of semiconductor. Score / Page 2