Circuit Diagram of FM Transmitter:

 The circuit use only single Transistor but good voice quality. This circuit is vary simple and uses few components. Main parts of the circuit is R & C (Resistance & Capacitor) circuit to produce RF at Required Frequency band.

At FM receiver side Radio waves (oscillating magnating lines) produces current in Arial. Which is further amplified,  Demodulated and feed to a speaker.


Parts List:


Capacitor =10Mfd, 0.1Mfd, 0.001Mfd, 2.2pf, 4pf, 5pf, 27pf, 68pf.
Resistance =3.3K, 2.2K, 3.9K, 220Ohms.
Transistor =494B
Mic =Condenser Mic
3v Battery with Container, switch Arial

Making Automatic Street Light

• Needs no manual operation for switching On and OFF. When there is need of light it automatically switches ON. When darkness rises to a certain value then sensor circuit gets activated and switches ON and when there is others source of light . Day time the street light gets OFF. The sensitiveteness of the street light can also be adjusted. In our project we have used L.E.D for indication of bulb but for high power switching one can connect Realy (electromagnatic switch) at the output of pin 3 of I.C 555. Then it will be possible to turn ON/OFF any electrical appliances connected all the way throught realy.

Component used:
9v Battery with strip switch.
L.D.R (Light Depending Resistance)
I.C NE555 with base.
L.E.D (Light Emitting Diode) 3 to 6 picess.
Vriable Resistance of 4.7 kilo ohms .
P.C.B (Printed Circuit Board of 555)

Components:

• Battery.
• L.D.R (Light Depended Light)
• L.E.D (Light Emitting Light )
• Variable Resistance.
• P.C.B (Printed Circuit Board)

Working :

When light falls on the LDR then its resistance decreases which results in increase of the voltage at pin 2 of the IC 555. IC 555 has got comparator inbuilt, which compares between the input voltage from pin2 and 1/3rd of the power supply voltage. When input brightness, input voltage rises so we obtain no positive voltage at output of pin3 to drive realy or LED, beside in poor light condition we get output to energy.

Clap switch making diagram

Here is a hobby circuit for Electronics hobbyists that can switch on & off Light, Fan, Radio etc. by the sound of clap. The sound of clap is received by a small microphone that is shown biased by resistor in the circuit. The microphone changes sound wave in to electrical wave which is further amplified by transistor. Transistor is used as common emitter circuit to amplify weak signals received by the microphone. Amplified output from the collector of trensistor is then feed to the Bistable Multivibrator circuit also known as flip-flop circuit.


Circuit Diagram of Clap Switch:

Parts list:

Resistors


R1=15KΩ,R5,R6=1.5KΩ

R2,R11,R12=2.2MΩ,R13=2.2KΩ

R3=270KΩ,R4=3.3KΩ

R7,R8=10KΩ,R9,R10=27KΩ

Capacitors: 

C1= 1000µf/16V
C2.01µf,C3,C4=.047µf

Semiconductor:

Q1,Q2,Q3=BC548, Q4=BC368

D2,D3,D4=IN 4148  

D1,D5=IN 4007, 

Others:
 
T1=12V/500mA X-former

Mic=Condenser Microphone

K1=12vRelay,B1=Bulb or Load. 

Complete circuit you see :--------