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Discover the secrets behind the magic light effect seen in movies like Harry Potter. Learn about resistors, capacitors, transistors, ICs, and more. Hands-on project included!
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What is Magic Light..?? • As we all know in some of the harry potter movies we had seen lights gets on by a simple clap or the sound produced by the fingers. • Is there a mystery behind it..? • Is it a real magic..?
No not at all • Then what is the principle behind the working of the light can u guess..?
Components Required • 6Volts to 9Volts supply • NE555 timer IC • 7474 IC • Transistor BC548,BC187 • Capacitor 0.1MF,1MF • Resistor 10K,1M,2.2K,220K,100ohm • Condenses mike
Advantages of learning Magic Light • Exposer to the components like resistor capacitor, transistor and IC can be known which is the basics of electronics engineering. • Conversion of the signals to one form to the another form is known. • Concepts about the voltage current and resistivity is covered. • Relations like V=IR can be known.
What is Resistor ? • What is IC ? • What is Transistor ? • What is Capacitor ?
How does the Magic Light work (only for the facilitators) • Here the 555 IC operates in monostablemultivibrator mode. It can be triggered with a low voltage at the 2nd pin. • The collector voltage of BC 548 is connected to the trigger pin of 555. • High amplitude sound signal in front of the condenser mic, turns ON the transistor BC 548. • Then its collector voltage falls to low, and the 555 turns ON for a time 1.1RC sec. • Output of the 555 is connected to clock input of D-flip flop (IC 7474). It is a -ve edge triggered flip flop. When the Monostable output goes to zero, flop-flop’s output Toggles.
The D-flip flop works as follows (only for the facilitators) • Its output will be the input only after a clock pulse. Without the clock, output will be the same i.e. it will not affects the inputs. • When Q’ is connected to the D input, (say Q’=1) for the 1st clock pulse, Q=1 & Q’=0, for the next clock pulse Q=0 & Q’=1. • That is (For time being consider flip-flop out is zero), for the 1st -ve transition output of the flip-flop goes to high and for the next -ve edge, output will be low. It will continue for successive -veedges • In this way we can hold the output as low or high. • The flip flop out is connected to a relay, when the output of flip flop is high it will energize the relay coil. • So the bulb connected on the relay will light up/down with each clap or any
What is IC ? It is nothing but integrated circuits. • What is Transistor ? It is a three terminal device which has Emitter, Base and Collector. • What is capacitor ? Adevice used to store an electric charge, consisting of one or more pairs of conductors separated by an insulator.
what is resistor ? Adevice having resistance to the passage of an electric current. • What is timer IC NE555 ? The 555 can be used to provide time delays. • What is Flip-Flop ? In electronics, a flip-flop or latch is a circuit that has two stable states and can be used to store state information.
Some basics of the transistor operation • Transistors of about 2 types NPN and PNP • What is NPN transistor then ? NPNconsisting of a layer of P-doped semiconductor (the "base") between two N-doped layers. • What is PNP transistor then ? PNP consisting of a layer of N-doped semiconductor (the "base") between two P-doped layers
Some of the symbolsto be known in electronics • Symbol for resistor • Symbol for variable resistance • Symbol for capacitor
What is polarized and non-polarized then ..?? • Polarized capacitor are those which have negative and positive poles • Non-polarized capacitor are those which do not have negative and positive poles • So then what is the below figure you call… can anyone guess..?
Symbol for VCC (+ve supply) • Symbol for ground (-ve supply)
So what is the EmitterBase collector then ? • The BASE - which is the lead responsible for activating the transistor. • TheCOLLECTOR - which is the positive lead. • TheEMITTER - which is the negative lead.
Let us know something about signals ? • What is a Signal then ? In electronics, a signal is an electric current or electromagnetic field used to convey data from one place to another. • The simplest form of signal is a direct current (DC) that is switched on and off. • More complex signals consist of an alternating-current (AC) or electromagnetic carrier that contains one or more data streams.
DC and AC signal Symbols • Can anyone tell which is AC and which is DC signal in this below figure.
So let us start the practical session • Before starting connection we need to know about the breadboard connections the below figure shows the connections of the breadboard.