This is a very low power rating and the minimum available one is of ¼ Watts. So, we have to choose 47Ω Resistor (the next available one).Ĭoming to the power rating of the resistor, it is equal to 1.2 * 0.03 = 0.036. From this, we can calculate the resistance as R = 1.2 / 0.03 = 40Ω. each LED will have a voltage drop of 3.6V across it.Īs a result, the voltage drop across the resistor will fall down to 12 – 3*3.6 = 1.2V. As three LEDs are connected in series, all the LEDs will have a voltage drop of 3.6V i.e.
Since the LEDs are connected in Series, the current through all of them will be the same i.e. The following image shows the circuit diagram of the LEDs in Series.
#5252F CHIP DIAGRAM SERIES#
In this circuit, we will connect three 5mm White LEDs is series with the same 12V Supply. The next circuit in the Simple LED Circuits project is connecting LEDs in series. Circuit 2 of Simple LED Circuits (LEDs in Series)
Once the right resistor is selected, we can connect the resistor in series and give the 12V Supply to the LED. To be on the safe side, we always have to pick the next possible value and hence we have chosen a ½ Watt (0.5 Watt) Resistor. Substituting these values in the above formula, we get the power dissipated by the resistor. So, the current through the Series Resistor is The current through the Resistor is same as the current through the LED as they are series. So, the Voltage Drop across the Series Resistor is We know that supply voltage is 12V and Voltage drop across LED is 3.6V. I RES is the current through the Resistor. Here, V RES is the voltage drop across the resistor and The Power Rating of a Resistor can be calculated using the following formula. Power Rating of a Resistor specifies the value of power that a resistor can safely dissipate. Now that we have calculated the resistance of the series resistor, the next step is to calculate the power rating of this resistor. Since there won’t be a 280Ω Resistor, we will use the next big resistor i.e. Substituting these values in the above equation, we can calculate the value of Series Resistance as Therefore, V S = 12V, V LED = 3.6V and I LED = 30mA. In our simple LED Circuit consisting of a single LED, we have used a 5mm White LED and a power supply of 12V.Īs per the datasheet of the 5mm White LED, the Forward Voltage of the LED is 3.6V and the Forward Current of the LED is 30mA. I LED is the desired current through the LED. V LED is the voltage drop across the LED and Here, V S is the Source or Supply Voltage The value of the series resistor can be calculated using the following formula. So, selecting the right resistor with the right wattage is very important. Connecting a small LED to a 12V Supply would burn the LED and you can see the magic smoke instantly. The important component (other than the LED of course) is the Resistor. The following image shows the setup of single LED connected to a 12V Supply and a current limiting series resistor. The circuit diagram for this circuit is shown below. We will try to turn ON a single 5mm White LED using a 12V Supply. The first circuit in the simple LED Circuits is a single LED Circuit.
Components Required for LEDs in ParallelĬircuit 1 of Simple LED Circuits (Single LED Circuit).Circuit 3 of Simple LED Circuits (LEDs in Parallel).Circuit 2 of Simple LED Circuits (LEDs in Series).Circuit 1 of Simple LED Circuits (Single LED Circuit).So, in this project, which is more of a tutorial, we will build some simple LED circuits like a simple single LED Circuit, LEDs in series, LEDs in parallel and high power LEDs. For small projects like blinking an LED, we need not worry about burning LEDs as we can connect a small resistor (like a 330Ω) in series with the LED (for a 5V supply).īut as the complexity of the circuit increases, choosing the right resistor with right wattage is important. Wrong voltage or current to LED will burn them off. Beginners in electronics often start with LEDs and the first project would be blinking an LED. LEDs are very sensitive components with respect to voltage and current and they must be provided with rated current and voltage values. Some of the common LED projects are LED Running Lights, LED Light Bulb, LED Knight Rider and LED Flasher. Students, hobbyists and makers often work with LEDs in different types of projects. Home lighting, office lighting, Automobile lighting, Street lighting etc. Nowadays, people are investing more in LEDs due to their energy efficiency. In this project, we will build few simple LED Circuits.
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