Electronic Project Samples

MY CONTACT NO. IF YOU NEED PARTS OR LIKE TO ASSEMBLE THIS FROM ME : +91 0 9818479606, +91 0 9250950118 (email: s i c c n o i d a @ g m a i l . c o m)

LIST OF SOME COMMON AND UN-COMMON ELECTRONIC CIRCUIT WITH PRICE:

1. Wind Mill (Class 1,2,3,4,5,6,7,8,9,10,11)............... Price (CLICK HERE for Price Page)
2. Electronic Eye Using IC555. (Class: 12th, B.Tech).... Price  CLICK HERE for Price Page
3. Military Alarm System with Buzzer ...................... Price Rs.  2000, 2500, 3000
4. Rain Water Alarm Using Transistor as a Switch...... Price (CLICK HERE for Price Page)
   (Best for Class 5,6,7,8,9,10, 11, 12)
5. Water Level Indicator Using Transistor as a Switch ... Price (CLICK HERE for Price Page)
   (Best for Class 5,6,7,8,9,10, 11, 12)
6. Automatic Car Garage Door..... (Open when car comes).... Price (2000,3000,4000,5000)
   (Best for Class 10,11,12, B.Tech. Electronic Diploma Students etc.)
7. AC / DC Transformer
8. Step Down Transformer Using Bridge Diode ........ Rs. 2500.
   (Full Wave Pure DC Getting Theory)
9. Step Down Transformer Using Double Diode .......  Rs. 2200
   (Full Wave Rectifier Theory)
10. Step Down Transformer Using Single Diode .......... Rs. 2000
    (Half Wave Rectifier Theory)

1. MEDIUM WAVE (MW) VOICE TRANSMITTER:  Here is a circuit for a Medium Wave Transmitter which can be assembled within a MW
   
   antenna coil. It is so small and portable that it can be put in a small match box or cigarette box etc. The modulation in this transmitter is purely AM. During transmission it works on MW receiver (Radio set).  It runs from 1.5V to 15V or on a single watch cell. In open area where high tension tower (250V - 440V) lines exists, the range of single reception is more than 500 meters.  If power supply is via battery eleminator.  The transmission frequency of transistor (T₁) lies above the MW frequency range.  The condenser mic(M) gets electrical sound pulses which it applies to the base of the oscillating transistor (T₁). Here the sound signals is amplified modulated on the carried frequently and transmitted by the Antenna (A).  Antenna should be one meter long and of insulated wire.
   COMPONENTS USED:
   ---  R1:   10K  (1/4 watt)       ---  R2:   47K  (1/4 watt)
   ---  C1   :   0.01 uf                  ---  C2   :   470P---  C3   :   10 uf---  T1   :   **********)---  Other components on demand ....... (circuit diagram and other details fee applicable)
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2. SHORT CIRCUIT INDICATOR CUM - SHORT CIRCUIT PROTECTOR: Let us imagine a situation that we are experimenting with new circuits or 'Electrical Gadgets' in our home, or doing some Electronic / Electrical experiment in our Physics Lab !! Suddenly we face a Short Circuit !! i.e. the short curcuit can lead to overheating and destruction of costly devices.  Now What to Do !!................... Here is a Solution:
   
   This circuit is built around transistor T₁ and T₂ Form a complementary emmitter follower,
   
   whose output is available at the emitter of T2.
   
   Under normal conditions, Diode D1 is reversed biased & T₁ and T₂ are in conducting state.  The output is taken through the parallel combination of Diode D3 and Resistance R4.7 Ω (ohm).   The exreen LED  D2 which is connected to the output through current limitating resistor, indicates the normal functioning of load.
   
   In case of a short-circuit, D1 starts conducting and brings T₁ and T₂ almost out of conduction. Thus the power supply going to the load is almost cut off.  This condition is indicated by the dim glow of red LED D1.  The circuit resumes power supply going to the load when the short circuit is removed.
   
   A sufficiently large heat sink should be used with T₁ as it will dissipate a lot of heat.  The circuit can handle up to 500 mA current.  For larger currents you can rebust it to transistor AD149.
   
   COMPONENTS USED:
   1. -------     1.5  K Ohms Resistance   --------- 01 No
   2. -------     10   K Ohms Resistance   --------- 01 No
   3. -------     2.2  K Ohms Resistance   --------- 01 No
   4. -------     1     K Ohms Resistance   --------- 02 Nos
   5. -------     5     K Ohms Resistance   --------- 01 No
   
   6. -------     T1  Transistor (SK 100)   --------- 01 No
   7. -------     T2  Transistor (RC 148)   --------- 01 No
   8. -------     LED (Red) ..................................  01 No
   9. -------     LED (Green) ...............................  01 No
   10. -----     D3 (Diode) .......... IN4002............ 01 No
   11. -----     Capacitor (C1   1000 Mfd.  - 16V.. 01 No
   12. -----     Wires (approx 1 mtr)...................... 01 meter (approx)
   13. -----    Soldring Iron, Soldring Paste &
                    Soldring Wire ...............................  01 Nos each
   14. -----    PCB (Printed Circuit Board) ......... 01 No.
   .
3. WIRELESS RECORDING (LANDLINE PHONE): (Please do not use this device for spy or spying purpose as this is illegal activity):
   Basically we do recording from Audio CD to CD or DVD, or in olden days from one Tape Recorder Cassette to another Cassette - which is often associated with electrical noises.  To avoid this, inductive recording is done,  which is superior as compared to direct electrical recording.
   
   For such recording from any source of sound, the sensor is placed near the speaker or
   
   Telephone Wire or Earphone, the Headphone / Earphone pin is inserted into the external mike jack of tape recorder, which is set into the recording mode.  In this way, recording free from surronding noises and electrical disturbance is done.
   
   The circuit works with two pencil cells which last quite some time due to low consumption of power.  The sensor is home-made by winding 24 SWG enameled (insulated) copper wire on the whole length of a flat ferrite rod (used with antenna coil in a pocket radio set).  The sensor is placed near the speaker and the jack is inserted into the tape recorder's socket in recording mode.  The volume or voice being recorded is adjusted to give distortationless recording.
   
   This circuit can also be used for tape recording 2-way conversation going on a telephone.
   
   COMPONENTS USED:  Antenna Coil, BC 147B, BEL 188, Resistance 1.5 K, Mic Jack (2pin jack), R1 100K, Power Source 3 Volts, Condensor C1 0.1 micro farad.
   .
   .
4. SOUND OPERATED MUSICAL BELL:   We all notice that sometime ringing or pressing the "Simple Door Bell" or "Peon Call Bell" or "Doctor / Patient Call Bell" --- pressing Manually !! is not possible when we are holding something in our hands (or sometime for physically handicapped or physically locomotive disordered People like Handicapped).  This sound-operated 'Musical Melody' bell takes care of the problem.
   
   In this circuit, the use of an external relay has been eliminated.  The circuit comprises a triger stage (around BC 548 B) is biased in class C operation.  Every sound causes triggering at pin 2 of Timer IC NE555.
   
   When Variable Resistance VR1 is at maximum, the hold-on time of 555 is around 30 seconds.  But this time period can be set to a lower value by VR1, as per requirement, using the relationship:    
                                                  T   =    1.1   x   VR1   x    C1
   where VR1 is the actual resistance of the preset in circuit.  UM66 IC has ROM memory of 64 notes which are produced one by one and then over with a gap of about half second and they start again.  Transistor SL100  can be replaced by transistor BD 115.
   
   When the condensor mic. receives the sound of a clap or or any huge Tik Tok sound from our mouth, ......... the timer is triggered and the output at pin 3 of IC 555 goes high which gets applied through diode IN4001  to  pin 2 of musical IC UM66.  As UM66 gets the positive supply,  it starts giving electrical fluctuations of the music to the base of SL100, and a charming music comes.
5. ultra sensitive temp. sensor
6. as the name of the project already indicating, this gadget is very sensitive for measuring
7.  the temperature sensor,
8. in the circuit diagram,figure the long tailed differential amplifier,amplifies  and records the difference of the input voltage, The thermistor used is of the negative co-efficient type ( NTC),
9. resistance falls with temperature. A large change in conductivity with temperature places a limitation upon the use of semiconductor devices in some circuits. But in this case it is
10. exactly this property of the thermistor that is used to advantage. The thermistor consists
11. of sintered mixtures kof oxides such as Nio, Mn2o2 and co2 o3. By including the thermistor in the circuit it is possible to compensate for temperature changes over a range as wide as 100° c.
12. set the resistance 4.7k and 50k (R1) so that meter  reads zero, keeping the thermistor in ice.
13. Now immerse the thermistor in a hot water bath at 100deg c, and adjust the variable resistance
14. of 2k, to get a full scale deflection. The thermistor is now set and ready for use. To measure
15. any temperature, put the thermistor in contact with it. This way the thermal equilibrium is attained. The temperature is obtained directly on the meter. However, initial markings of the
16. meter should be made to get accurate readings. For this, measure known temperatures, and mark them on the meter dial.
17.    Parts Required
18.   1) TRANSISTOR---AC125 (6 nos ).
19.  2) RESISTANCE--- 1.2k (2 nos.), 1.5k,3.3k,10k,12k(2 nos.) 30k, 47k (1/4 WATT)
20.     1om, 100 om, 680 om, (2No.). ( 1/4 WATT) 50 om, 2k (VARIABLE RESISTANCE)
21.  3) METER   0-5V.
22.   4)THERMISTOR-NTC TYPE, 10K,-t temp c.
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27. DIGITAL RECORDING
28. this electronic gadget gives a numerical display of the number of input pulses.these pulses may come from any light activated device, such as LDR (LIGHT DEPENDENT RESISTENCE) or
29. through a mechanical switch.This gadget may be used in any counting operation, for measuring the RPM, or for recording the number of people leaving or entering a particular place. In the circuit diagram as is fig. 8, LDR is used as a triggering device for the decade binary counter IC 7490.However one may choose any other suitable triggering source to suit one's personal requirement.
30. The gadget consists of two IC'S, IC 7490 and IC 7448. The output of IC 7490 is transferred to IC 7448, which in turn operates the Seven-Segment indicator is of the common cathode type, and the cathode is grounded. The various combinations of output from IC 7448 result in the formation of digits from 0 to 9.
31. When the reset switch ( NORMALLY CLOSED TYPE) is pressed, 0 is displayed on the 
32. Seven-Segment Indicator. Now, when the first triggered pulse reaches the pin 14 of IC 7490, digit 1gets displayed. Similarly when the 9th pulse reaches the pin 14,digit 9 is displayed. 
33.  On the arrival of the 10th pulse, digit 0 is displayed.   This process repeats itself depending upon the number of pulses received.
34. Pulses for IC 7490 are generated by LDR, which is generally kept illuminated, With each    
35.   light interruption in the LDR, the corresponding digits are displayed on the Seven-Segment 
36. indicator.
37. PARTS REQUIRED
38. 1) IC,7490, IC 7448.
39. 2) LDR-1 No.
40. 3) SEVEN-SEGMENT INDICATOR-COMMON CATHODE TYPE
41. 4) RESISTANCE-100K (PRESET) ¼ WATT)
42. 5) SWITCH-N/C RESET

THE DUAL ROLE

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This gadget "The Dual Role" may be used as

a) Continuity Tester

b) Musical Instrument 

     The Continuity Tester is capable of measuring almost the complete range of resistors. When the

circuit diagrams, fig:9a & 9b, are coupled together, they function as a variable tone musical instrument. The output of this musical instrument may be connected to an ordinary amplifier to get better sound effects.

In the circuit diagram,fig 9a, when used as separate, acts as a Continuity Tester. The points A&B act as the probes. Since the current through the probes is very small (few Micro-Amps), it can be safely used for determining the forward and reverse continuity conditions of devices, such as, transistors, diodes, etc. Apart from checking the continuity, this gadget also gives an idea regarding the resistance of the device under test. The notes of the tone produced form the speaker, varies with the resistance of device under test.

Suppose the device under test is a diode. In the forward continuity conditions, diode offers a small resistance as compared to that, in the reverse continuity conditions. The notes produced by the speaker should differ, when diode is placed in the forward and reverse continuity conditions. If the notes are of the same tone, then it indicates that diode is short. And if no notes are produced, diode is open. Similarly other devices can also be checked.

The circuit diagram, fig,9b, is nothing but a network of variable resistors. When connected to the probes A and B of circuit diagram (fig.9a) variable notes are produced when the, the sliding switch is slided. The resistance varies, thereby producing different notes. Each step of variable resistor network

is provided with a 10k preset, which can be adjusted to get desired notes.

Parts Required 

1) TIMER - IC 555

2) TRANSFORMER - OUTPUT TRANSFORMER PRIMARY SECONDARY 400 : 8

3) CONDENSER - 0.01 uf ( POLYSTER)

4) RESISTANCE - 18k, 24k, 680 OM ( 1/4 watt )

5) SPEAKER - 8 OM

For Fig. 9-b

1) RESISTANCE - 10K MULTIPLY 5 ( PRESETS )

2) SWITCH - SLIDING TYPE



THE BRAINY DOOR


Want to catch a thief red handed ? Here is how you can do it. Fix this gadget in your garage near to the door, where a magnet is fixed. Now as soon as the door is opened, the gadget will function and sound off an alarm, and that is the moment when you get into action. You can use this gadget for
protecting other valuable things also.