Compare two-pin and one-pin lamp

Lamps that are used in the lighting system of a car (headlights, interior lighting, parking lights, brake lights, and so on) can be single-pin and two-pin. And they differ not only, as the name implies, in the number of contacts, but also in functionality. And, of course, they are not interchangeable.

Let’s figure out how a two-pin lamp differs from a single-pin one and whether it is worth modifying the lighting system for two-pin ones.

Briefly about the work of lamps

Automotive lighting systems use mostly standard incandescent bulbs. In fact, they are a resistor, which is connected with one contact to the «plus», and the second — to the «minus». When current is applied to both, the incandescent coil heats up and begins to shine. Actually, as in ordinary light bulbs installed in houses and apartments.

There are two contacts for a standard incandescent lamp, including 1-pin ones. One is for plus, the other is for minus. The contact to the «minus» is displayed on the base, its metal part, on which the thread or the fixing «eye» is located. «Plus», in turn, is located on the bottom of the base.

How single-pin and two-pin lamps are arranged

For a single contact light bulb on the bottom of the base there is one «positive» contact. It goes directly to the incandescent spiral and there it closes with a negative one.

For a two-prong light bulb on the bottom of the base there are two «positive» contacts. Each of them goes to a separate incandescent spiral. That is, such a lighting device has two incandescent spirals. But the negative contact is one, common, located on the metal part of the base.

LED devices also come in single-pin and two-pin. In the first case, they are equipped with one chip and one set of LED elements, and in the second case, they are equipped with two chips and two sets of LED elements.

It is clear that two-prong devices require a special cartridge. In a standard, designed for one contact, you can not install them. In addition, the glass dome of such bulbs can be larger than that of single-contact bulbs and have a special shape.

Basically, such devices are used in stop and side lights. Less often they are installed in the «turn signals». In headlights, regardless of type, they are practically not used, with extremely rare exceptions. It is also not recommended to install them yourself, as they increase the load on the car’s electrical network. And the headlights “burn” almost constantly, and their increased power can be dangerous for cables, generator and battery.

In most cases, the power of the second spiral is much lower than the first. This is due both to attempts not to bring to an overload in power, and to comply with the requirements for the brightness of automotive lighting equipment.

Is it worth it to change single-pin lamps to two-pin ones?

The main advantage of two-pin incandescent bulbs is that they give twice as much light. This is especially useful when driving in fog, in urban environments with heavy «light pollution» of the space, and in other cases where it is necessary to highlight the lights.

But LED two-pin bulbs do not give more light. But they reduce the load on the car’s electrical network, since the power transmitted along the «plus» or «minus» is reduced. And not twice, but a little less, since the laws of electrical engineering come into play here.

It is worth noting that, despite all the advantages of two-pin light bulbs, remaking a car for such equipment can require a lot of effort. Would need:

1. Connect two relays for parking lights and brake lights;

2. Run two additional power cables — for example, from the cigarette lighter.

3. In addition, such lighting equipment can cause many additional questions during inspection. If you don’t want to call the inspector’s extra attention, it’s better to do without such a “collective farm”.

Connecting additional relays will reduce the load on the vehicle’s electrical wiring. You can also install toggle switches — thanks to them, the inspector will have much less questions during the inspection. You will also need to replace the plinths or slightly modify the existing ones by drilling a groove in it for the second lug.

When choosing lighting equipment, you should also pay attention to the power of the device. The optimal solution would be configurations for 21 W / 5 W, or options similar to existing equipment.

Before modifying a 1-pin cartridge into a 2-pin one, you should make sure that the “minus” covers its entire lower part — and then the appropriate lighting equipment can be installed in the device.

However, such «collective-farm improvements» are not recommended. They bring with them two problems. Firstly, the load on the electrical network of vehicles will increase, which in some cases can be fraught with serious breakdowns. Secondly, unnecessary questions may arise from traffic inspectors.