Perhaps you just changed the wiring of your LED light, and now it is not lighting up. Undoubtedly, there could be several reasons your light is not illuminating. Sometimes, the incorrect polarity of lights might be the culprit.
The wrong polarity of a LED light is a scenario that occurs when a Light Emitting Diode (LED) does not get electrical current flowing in one direction.
LED lights work appropriately only when their positive terminals (anodes) are connected to the positive supply. Similarly, their negative terminal (cathodes) must connect to the negative supply.
In this post, we will gain in-depth information regarding the polarity of LED lights. Before that, let us learn what is polarity in general.
The polarity of Light Overview
Two different voltage polarities present in an electric circuit define its polarity. These include:
- Direct Current
- Alternating Current
We refer Direct Current (DC) as the current that flows from positive to negative. On the contrary, the current that passes from negative to positive is the alternative current (AC).
In a DC circuit, you can see the mark of polarity as + and -. As a result, you can easily find where you need to connect the power supply.
What is The Polarity of LED Light?
An LED light has diodes that allow electrical current to flow in one direction. It is called the polarization of LED light.
The positive pin of an LED light is the anode (+), while the negative pin is known as the cathode (-).
Like with other lights, the polarity also matters to LED light. An electronic polarity signifies if the circuit is symmetric or not.
If you wire your LED light backward it might burn the whole system.
The current travels from the anode terminal and reaches the cathode terminal. Consequently, you must connect your LED light to a circuit in the same direction. Otherwise, your LED light will not turn on. In short, you must know how to wire up your LED light correctly.
How Does The Polarity Work?
Most LED diodes have metal legs pointing out what terminal you should connect to. The way you connect them to the power supply can change their working.
For example, if you connect them to reverse voltage, they might flicker. In some cases, they can get permanently damaged. After all, reverse polarity cancels the electrical charge making an LED function.
Do LED Lights Have Polarity?
It is one of the popular questions asked about LED lights.
There are a lot of misconceptions about the polarity of the LED light. However, we can say LED lights are polarity sensitive.
Like most bulbs, they also have positive and negative connections. If you do not wire their circuits accurately, they will not illuminate.
When you do not connect the wire to the right terminal, the voltage is in the wrong polarity. It is known as reverse-biased. Since a low current passes in the LED bulb, it does not light up. Let us get to know what other things can happen in case of a backward connection.
What If your LED Light has a Backwards Connection?
If you have mistakenly wired your LED light into a circuit with the cathode and anode backward, it will not damage your light. Nevertheless, your LED will not light up. If the voltage in the circuit is between low to normal.
However, if you do not connect wires correctly, and the voltage is extremely high, your LED light might get damaged.
It can overheat or burn your LED bulb.
If you accidentally connected your LED reversed, change it. It should not be a big deal. The challenging part is that it is not easy to find the incorrect polarity of the LED light.
In most cases, you cannot see it with your own eyes. So how can we find it out? Yes, we have accumulated some easiest ways for you below.
How Can You Look for the Accurate Polarity of LEDs?
Whether you are a seasoned electrician or just experimenting with the connection of your LED light, you may mistakenly install connections the wrong way. Nevertheless, below are a few easiest ways to determine the right LED polarity.
The difference in Leads’ Length
The first thing you can do is, check the difference in the length of leads. Some inexperienced people think that it is a manufacturing defect. However, it is not.
The lead length is one of the easiest ways to determine the polarity of the LED. If you have purchased new LED lights, look at their strings. The shorter lead is negative, while the longer lead is positive.
If you have already used LEDs in a project or they are soldered, you will not be able to see this difference.
See The Flat Side
Another thing you can do to check the polarity of LED lights is that see their flat side.
Most LED companies make one side of their LED bulb flat. The rounded side is often positive (+), while the flat size indicates negative (-).
Difference in Plate
If you take a closer look at the details of your LED bulb, it can tell you if your LED is correctly polarized or not. See the two metal plates inside your LED light.
You will notice that one is small while the other is big. You need to connect a bigger plate to the negative lead. Similarly, connect the smaller plate to the positive lead.
Unfortunately, not all LED bulbs have these differences. If you do not find these signs with your LED bulbs, you can try the following methods.
For those who do not know, a multimeter is an electronic instrument that measures multiple electrical properties. It is also known as VOM. You can use it to compute a resistor value in no minute.
Almost all multimeters are capable of measuring diodes. Therefore, you can use them to determine the polarity of LED bulbs.
Simply, touch the multimeter’s probes to the bulb’s connection or lead. Check if it is shining. If it does not shine, swap probes. It should work fine now.
Remember, the red probe connects to the positive lead, whereas the black probe connects to the negative lead.
Some multimeters do not make the light glow dimly. In that case, you can check the number on the display of your multimeter.
Ensure the cathode and anode is not in contact during the test. Otherwise, it might deter your results.
If the probes are touching the cathode and anode, the LED bulb should display a voltage of about 1600 mV. If you do not see any result on the screen during the test interchange the connection.
It is one of the quickest ways to check the polarity of the LED. Also, it helps you check if the light is dead or not.
However, you will have to invest in a multimeter for it. A regular mid-range multimeter should cost you between $50 and $100. If possible, choose a digital multimeter over an analog one. It makes reading easier.
Coin Cell Battery
A small coin cell battery, which is used in watches, can also help you determine the polarity of the LED light. If you are not an electrician or do not deal with such situations regularly, you can use a coin cell instead of a multimeter.
It is one of the safest options to check the polarity of LED lights. Coin cell batteries do not produce enough current to harm anything. Moreover, you can easily buy these batteries online or from pharmacies, hardware stores, and departmental stores.
Moreover, due to its small size, you can fit it between both leads of a light-emitting diode. If the bulb shines, it means it has the correct polarity. If not, swap the battery. Thus you can learn whether the connection is symmetric or not.
You can choose CR2025 or CR2032 cell batteries. Nowadays, some batteries come with holders. It makes it easier to connect wires to the cathode and anode. Still, if your LED bulb is not lighting up, it could be defective or burnt.
Besides the coin cell battery, you can use the AA battery. You can connect it to the LED with the help of cables.
Does Polarity Make an Effect On LED Light Power Consumption?
As mentioned above, connecting LED lights wrongly does not cause any safety issues or damage. Generally, LED light bulbs to have internal circuitry which converts AC into DC. Therefore, bulbs illuminate.
However, if these circuits fail, you will not get any electricity. In some cases, you can get too much electricity flowing through your device.
In the latter scenario (too much electric flow), your device will get damaged.
So this is an in-depth article on the polarity of LED lights. We hope it gives you enough clarity.