How does a dual filament bulb work? Rearlights

To put it simply, it is like "two" parallel lights, there is a switch on the headlights and brakes, and the brake bulb is powerful, so when braking, it is brighter than the rear tail lights to prompt the car behind!

You can do an experiment and unscrew the bulb, and you will find that the bottom of the bulb is three points, I don't know if the positive pole is universal or negative! You turn on the battery and find two switches (like the tail light and the brake switch) to connect to the other two contacts, and you know the principle of the workpiece!

Its structural characteristics are that the metal sleeve is fixed at the center position of the threaded lamp mouth, the group filament lead wire is welded on the metal sleeve, the insulating cylinder with the center perforation is embedded in this metal sleeve, the group filament lead wire welded on the metal sheet passes through this center perforation, the metal gasket is provided with an insulating pad, the metal cap is sleeved on the metal sleeve, and the double filament bulb can be used sequentially with the group filament and the group filament, prolonging the service life of the bulb, and the insulating pad can also be removed, and the group filament and the group filament are used simultaneously to increase the power of the bulb.

The dual-light wick headlamp system is a symmetrical low-beam system, and the left and right sides of the low-beam type are exactly the same, so it is suitable for driving on both the left and right sides. However, when the driving light (high beam) changes to the driving light (low beam), the visual distance is shortened, forcing the vehicle to reduce its speed. In order to solve the problem that in the process of meeting the car, the headlamp does not produce dazzle, but also can ensure that the road has good illumination, in 1932 the United States invented the asymmetrical headlamp, which is centered on the reference axis, the beam is divided into two, close to the side of the car landing distance is short (that is, the beam is depressed, so as to prevent dazzle) and the other side of the beam landing distance is long (that is, the beam is raised, thereby increasing the visibility).

The brake bulb contains a width indicator light and a brake light, so there are two filaments. The width indicator light is 5W, and the brake light is 21W. The headlights are divided into high beams and low beams, they are controlled separately, and its two filaments are one for high beams and one for low beams.

This is to install two filaments in a bulb, it is reasonable to have 4 wires, but in order to save the cost and reduce the complexity of the process, it uses a common wire, generally a common ground wire (GND) is usually the negative pole of the power supply, and the other two wires control the corresponding filament, which wire is added to the voltage, the filament connected to the wire will emit light, so that you can control the two filaments inside. It can be used for high beam and low beam. Low beams and high beams are not only different in power, the main principle is that the filament of the high beam is on the focus of the headlights, and the low beams are not there, so the high beams can shine far away.

So, we found that the bulb of that headlight is a bit long, and the two filaments are one after the other.

Because the brake light and the running light are the same bulb, they are double-filament.

Automobile brake lights, according to the position, are divided into three types: 1. Brake lights at the rear of the car; 2. The brake light on the dashboard of the car, that is, the brake indicator light; 3. High-mounted brake light. According to the materials used, it is divided into two types:

1. Gas car brake light; 2. LED car brake light.

Then what is the situation when my brake light is on and the width indicator light is not on?

1. Automobile double-filament bulbs have flat angles, and generally ordinary ones have flat angles.

2. Automobile double-filament bulb refers to two sets of filaments in the glass shell of the bulb, which are used in the high and near beams, tail lights and brake lights of the car, which can be lit separately or together. There will be no interference.

There are three binding posts at the rear of the H4 bulb of the car headlight, two of which are the live wires controlled by the headlight relay, and the other is the public tie wire, not all three wires are live wires.

There are two filaments inside the H4 bulb, one is a high beam filament and one is a low beam filament. When we turn on the low beam, the headlight relay is connected to the live wire of the low beam, and the current passes through the low beam filament and then returns to the negative pole of the battery through the common tie wire, forming a complete circuit, and the low beam is lit; In the same way, when we turn on the high beam, the headlight relay is connected to the live wire of the low beam and high beam at the same time, and the current passes through the low beam filament and high beam filament and then returns to the negative pole of the battery through the common tie wire, forming a complete circuit, and the high and low beam lights are lit at the same time.

The H4 bulb is a very low-end halogen bulb, its brightness is relatively low, and the service life is shorter, so now this kind of lamp is rarely used in passenger cars, and more xenon headlights and LED headlights are used. These two types of headlights are brighter, but the control circuit is more complex and requires a special controller, unlike the H4 bulb line.

If you say that the headlights are double filament, the most popular model is H4 12V60 55W, as shown below.

Of course, there are 9004, 9007, H13, etc., but these are not very common, and Japanese cars and American cars are generally used.