Led series and parallel connection

This PPT explains how to connect LED in series and parallel

1. LED – Series and Parallel Connection Dr.R.Hepzi Pramila Devamani Assistant Professor of Physics V.V.Vanniaperumal College for Women, Virudhunagar

2. Introduction A  light-emitting diode  (LED) is a semiconductor light source that emits light when current flows through it. ... White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. The LED is a special type of diode and they have similar electrical characteristics to a PN junction diode. Hence the LED allows the flow of current in the forward direction and blocks the current in the reverse direction. The lighting emitting diode is a  pn junction diode. It is a specially doped diode and made up of a special type of semiconductors. When the light emits in the forward biased, then it is called a light-emitting diode.

3. LED Symbol The LED symbol is similar to a diode symbol except for two small arrows that specify the emission of light, thus it is called LED (light-emitting diode). The LED includes two terminals namely anode (+) and the cathode (-). The LED symbol is shown below.

4. Working of LED When the diode is forward biased, then the electrons & holes are moving fast across the junction and they are combined constantly, removing one another out. Soon after the electrons are moving from the n-type to the p-type silicon, it combines with the holes, then it disappears. Hence it makes the complete atom and more stable and it gives the little burst of energy in the form of a tiny packet or photon of light.

5. Advantages The cost of LED’s is less and they are tiny. By using the LED’s electricity is controlled. The intensity of the LED differs with the help of the microcontroller. Long Lifetime Energy efficient No warm-up period Rugged Doesn’t affect by cold temperatures Directional Color Rendering is Excellent Environmentally friendly Controllable

6. Disadvantages Price Temperature sensitivity Temperature dependence Light quality Electrical polarity Voltage sensitivity Efficiency droop Impact on insects

7. Applications LED is used as a bulb in the homes and industries The light-emitting diodes are used in motorcycles and cars These are used in mobile phones to display the message At the traffic light signals LED’s are used

8. Series and Parallel Connection There are three kinds of connections of an electrical circuit or electronic circuit: serial connection, parallel connection, and series-parallel (combination circuit). The two that occur most are the easiest: serial connection, parallel connection. If we take Led lights, for example, they can be connected in a parallel or serial connection . A serial connection is when components are connected along a single path. A parallel connection is when components are connected along multiple paths.

9. Series Connection LEDs that are connected in a series, are connected along a single conductive way, so the same current runs through all of the components but voltage are lost over each of the LEDs. In a series circuit, the sum of the voltages used by each unique resistance is equivalent to the source voltage . A serial connection is required with LED lighting if you use a current-controlled power supply.

10. Series Connection Consider a circuit consisting of four LED light bulbs and a 12-volt battery. If a wire runs the battery to one bulb, to the next bulb, to the next bulb, to the next bulb, and then back to the battery in one unbroken loop, the bulbs are said to be in series connection as shown in Figure.

11. Series Connection In a serial connection, the current can’t continue and the LEDs are turned off. So whenever at least one LED is broken, the circuit is interrupted. The broken LED can no longer conduct the current so that all LEDs on the circuit break down.

12. Parallel Connection By using a parallel connection the voltage is split up and each LED is applied the same amount of voltage. If you use a circuit with just LEDs connected in series it’s a serial connection and if you connect them in a parallel way that’s known as a parallel circuit. A parallel connection is required with LED lighting if you use a voltage power feed.

13. Parallel Connection If each LED bulb is wired to the battery in a separate loop, the bulbs are said to be in parallel connection .

14. Parallel Connection With a parallel connection, the rest of the LEDs continue to operate even if one of the LEDs burn out, – The circuit stays intact.

15. Video LED – Series and Parallel Connection

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