5-pin SPDT (single pole, double throw) automotive relay.

Relays are essentially two parts in one package. The first part is an inductive coil (pins 85 and 86). This coil is the “trigger” function of the relay. By applying both a positive (+) and ground (-) to the contacts, current passes through the coil. When current passes through the coil, a magnetic field is generated and moves the switch (the arrow in the diagram). This is where the second part of the relay comes into play.

The second part of the relay is the “switch.” The switch has three interface contacts—common, normally closed, and normally open. “Normally” refers to the state of the relay not being energized.

While relays can be used for virtually any task, there are some very useful, simple applications for adding LED lighting to a vehicle. Please note that this wiring only pertains to the relay—not the wires in the vehicle. Before interfacing with a wire in a vehicle, always ensure you test the wire with a digital multimeter first to confirm circuit function.

Positive Switching

Positive switching is used for applications where the “trigger” for your switch or circuit is positive. This could be an ignition, brake, or reverse light wire for example.  This could be used for applications such as off-road light bars, work lights, additional brake lights, and other exterior lighting.

Negative Switching

Negative switching is used for applications where the “trigger” for your switch or circuit is negative. Negative triggers are often found in door, hatch, and trunk triggers as well as many interior switches. This could be used for applications such as footwell lighting, truck bed lighting, under-hood lighting, and other interior lighting.

Switch Activated With Ignition Override

This is useful for applications where you want to turn your light on or off with a switch but only want the light to remain on when the car is running or key is in the “ignition” position. The main advantage to this is—even if the switch is left on—the light (or output circuit) will shut off when the key is turned off so that the battery will not be run down.

For technical questions, don’t hesitate to call us toll free at 866-590-3533. Our customer service and technical support teams are available from 8:30 a.m. to 8 p.m. CDT Monday-Thursday and 8:30 a.m. to 4 p.m. CDT on Friday.

When you need electrical power but the nearest outlet is too far away for your device to reach, an extension cord can bridge the gap and bring the socket to you! Extension cords come in numerous shapes and sizes, and are intended for many different applications. However, are you choosing the right cord for your needs? Believe it or not, not all extension cords are created equal, and depending on the amount of energy you need and where you need it, you should carefully consider what cord you’re using. Check out our blog now to learn about the different types of cords and which one you should choose for the job.

While extension cords are great because they let you bring power virtually anywhere you need it, you should also think very carefully about where you will need this power, and where you plan on drawing the electricity from. Longer isn’t usually better, and in fact, the longer your extension cord is, the lower the delivered voltage will be. The more distance electricity must travel, the weaker it will be when it reaches you. This is because every cable has a certain amount of resistance, which causes your voltage to drop as well as produces heat. If you can help it, don’t use a 100-foot extension cord if you only need power about 20 feet away. You’ll bring better voltage over a shorter cable, and have less cable to manage during use as well.

On a related note, if you do have to bring electricity to a further-away distance, never link two extension cords together. This is a recipe for disaster. If you must bring electricity to a further-away distance, always upgrade to a longer cord that will meet your needs.

If you pull too much power through too small of a cord, you will draw too many amperes (or “amps” for short), and the cord itself being too small or having too much internal resistance will get hot and possibly fail, which could result in melting, sparks, and even a bad electrical fire. A device that uses more electricity, such as a major appliance like a stove or electric grill, should always be plugged into a larger-gauge extension cord, whereas smaller gauge cords are generally safe for use with things like laptop and phone chargers, low-energy lamps, and more.

Extension cords are a huge trip hazard, and the more you use one, the more likely it is that someone will eventually get tangled up and fall because of it. Be very cautious where you run your extension cords, and always make sure you secure them down with tape or cover them with a large carpet or rug to make sure nobody will accidentally become tangled in one.

If you own a business and find you are in constant need of an extension cord to a particular spot, you may want to consider calling a Marietta electrician and having them permanently install a new electrical outlet to get rid of the need to use an extension cord all together. This can significantly improve worker safety even save you money on your electric bill by helping your devices get the voltage they need easier.