FREE CIRCUIT DIAGRAMS 4U

TV Transmitter circuit diagram (VHF)

2012-01-21T23:29:00.000-08:00

Most of people ask TV transmitters.So Today I'm going to give you a very useful circuit diagram.By using this circuit you can send your signals 75m to 100m.This circuit diagram is not my own circuit one of my friends gave me this.I suppose you guys also can send your own circuit diagrams for us.Then we can publish them through our website.Here They have used common transistor BC 108 If you are unable to find this transistor you can use equal transistors like BC337, 2N2222, BC546.

Note

# To make L1 wound 6 turns of #24 enameled wire on a 10mm air former for frequency 60 - 80 MHz For 150 - 180 MHz wound 4 turns and for 180 - 200MHz wound 2 turns.

# This circuit operates with 9V power supply

# When you build this circuit you have to build this on a little space.

# The power of this circuit is 80mW

# use a pcb to build this circuit diagram.

# This is only for educational purpose.We can bear any responsibility of this If you misused this.

# This circuit transmit only video signals .If you want to send sound signals you can use an audio transmitter

Burglar alarm

2012-01-02T09:25:00.000-08:00

This is a very useful circuit diagram because these days there are lots of crimes in every where.So I suppose this would be an answer for your matter.Here I have used common Transistor BC107.After fixing this circuit switch on s1 and adjust R2 until the horn makes sound.Then switch off the s1 .Now if some one broke the thin wire the horn will make a sound.You can cover your garden with this circuit

Note

# Build this circuit on a PCB
#Don't supply more than 12V
# Use very thin wire to get good results

Basic Sound Generator Circuit Diagram

2011-10-17T22:17:00.000-07:00

This is so important circuit for the persons who came to this field recently.Here I have used common IC NE555.According to the pules (Frequency) of the IC We can generate the sound.You can change the speed of the sound by adjusting R2.This circuit operates with 5V.

# Note

# Don't give over 5V
# Build this circuit on a PCB
# Don't give the much heat to the IC NE555

Three sirens in one Circuit

2011-09-29T21:58:00.000-07:00

This is a siren circuit diagram Here I have used UM3561 circuit diagram.This circuit can be operated with 3V.It can generate 3 sirens.Here I have used IC 2SC9013 you can use the same IC or similar IC. Use 8ohm 0.2W speaker.

Note:-

* Don't use more than 3V
* Don't use this for unnecessary things
* Build this circuit on a PCB

230V LED

2011-07-25T21:58:00.000-07:00

Most of you asked about 230V LED circuit diagrams.Today I'm going to introduce you that circuit.I have attached this circuit for my door bell.So that at night I can easily see it.Not only that people can us this circuit to see whether electricity is there or not So use thi9s circuit and get fun....

# Note

# you should be careful when you use this circuit.Because this circuit operates with 230V
# This circuit is not suitable for kids
# When you use electronic parts those parts should have correct values(like W and V)

# Build this circuit on a pcb If the circuit doesn't work don't touch it.Firstly switch off the circuit.

Simple radio circit diagram

2011-05-13T22:36:00.000-07:00

some persons asked simple radio circuit diagrams.Here you can see very simple circuit diagram.When I tested this my first time I enjoyed very much.When the signals are coming you can here some sounds like ne ne nee nic nee nee nee nee.so test this and enjoy.

Note:

# Don't use more than 4.5V

# Build this on a pcb

#If the signals don't come move the main coil here and there then you can here some sounds.

# Firstly this circuit was designed by Elmer G. Osterhoudt in the early 30's

Simple Toy Orgen

2011-04-14T01:36:00.000-07:00

This is a toy orgen circuit diagram here I have used very common IC NE555.If you like to generate different sounds you can attach capacitors with different values.according to the value of the capacitor you can change the sound according to your wish.

Note

# Build this circuit on a PCB

# Don't use more than 9v

# Use only push to on switches

Smoke sensitive circuit diagram

2011-04-01T22:22:00.000-07:00

Here I am going to introduce you a very important circuit.It is nothing but a smoke sensitive circuit .In the market we can see there are lots of expensive smoke sensitive kits.But I'm going to give you a very simple method to make a smoke detector.Here i have used a dark sensitive circuit.When the smoke goes via LEDs and LDR it will generates a sound.If you want to operate another circuit firstly remove the speaker and add a really for there.then you can operate your circuit through that really.

Note

# Build this circuit on pcb

# Don't use more than 9V

#Use Blue colour LEDs

Water sensitive circuit diagram

2011-02-23T21:12:00.000-08:00

This is a water sensitive circuit diagram.I suppose this circuit will give you lots of benefits .I have modified this circuit up to some extent and have added to our water pump moter (230 v) I think you also can use this circuit for various purposes.Here I have used common IC Bc109. When you fix the sensor Don't forget to fix it over the water level.This circuit operates with 4.5V to 6v.If you want to operate your water pump 230V 0r 110V you can use a rellay for that.Then this circuit will switch on or off that rellay( use 6V rellay)

Note

# Use a PCB to build this circuit

# Don't supply more than 6V

#Don't forget to fix the sensor over the water level

Touch sensitive circuit diagram

2011-02-17T06:30:00.000-08:00

Here I have design a touch sensitive circuit diagram.For this circuit I have used a common transistor BC 547.Normally this circuit can be operated with 4.5 to 6 v.I suppose you will be able to do lots of things with this.I have used this circuit for my room light.So you also can use this circuit for your room light.

Note

# Use a pcb to build this circuit

# Don't supply more than 6V

Simple Flaher Circuit Diagram (24V)

2010-12-27T21:32:00.000-08:00

This is a simple flasher circuit diagram.Some people can't use normal circuit diagrams due to 24V batteries of there Vehicles.Here I Have introduced 24V circuit diagram for you all.Here I have used simple circuit diagram.It is multivibrator circuit .Here I have used famous transistor 2N3055.

Note

# Build this circuit on a PCB
# This circuit can be operated with 18V-24V

Blinking LED Circuit Diagram

2010-12-26T08:32:00.000-08:00

This is a blinking LED circuit diagram.Here I have used common IC NE555.If you want to change the speed of this circuit you can change the value of R2.Then you can do that.

Note

* Use a PCB to build this circuit
* You can operate this circuit with 9V

Simple Christmas star from multivibrator Circuit Diagram

2010-12-01T07:04:00.000-08:00

This is so simple circuit But you can use this circuit as a Christmas star.Here I have used famous transistor 2N3904.If you are unable to find this transistor you can use D400 instead of that.This circuit operates with 9V.I used this circuit for the last Christmas If you used Blue color LED s It would give inexpressible attraction.

Note

# If you want to change the speed of this circuit You can do it by changing the values of 10uf and 100k

# This circuit can be operated with 9V power supply

# Fix this circuit on a pcb

Flashing Neon Circuit diagram

2010-11-07T08:45:00.000-08:00

This circuit will be a fantastic circuit for Vehicle lovers Because this circuit can up grade the out look of your Vehicle. This circuit is nothing but a Flashing Neon circuit diagram.This circuit can be operated with 90V.You can change the frequency of this circuit by changing the values of C and R.Large values reduce frequency of this circuit.

Note

# Use Ne 2 or Ne 51

# This circuit can be operated with 90v

12V to 120V Inverter circuit diagram

2010-10-24T01:05:00.001-07:00

Most of members asked about 12V to 120 inverter circuit diagram.As they mentioned they need to operate 120V applicants with 12V car battery.So this circuit will be the answer for that.

Note

# T1 should be 15A

# parts that we have mentioned here can only drive 15 amps each.

# Use tantalum capacitors for C1 and C2 Because Regular electrolytic can be over heat

# Be careful when you deal with Ac 120V

# use a fuse for the circuit

Light Operated Rellay Circuit diagram

2010-10-03T21:11:00.001-07:00

This is light operated circuit diagram.Wonderful thing is this circuit can be operated with 9V power supply.You can attach this circuit for your vehicle even.I have used this circuit for my car as an automatic dim switch.This circuit operates with BC548 Transistor.If you want more info you can send us an email through our website email address.

Note

# Fix this circuit on a P.C.B

# Don't use more than 9V

Fluorescent Tube Light Driver Circuit Diagram(10W)

2010-10-03T00:28:00.000-07:00

This is very useful circuit for us.Because we can light up 10W Fluorescent lamp by using this circuit diagram.This circuit operates with single transformer.I suppose now you can enjoy this inverter.When you wind the transformer do it carefully because that is the heart of this circuit.

Note

# Be careful when you operate this circuit because high voltage is dangerous.
# This circuit is not good for kids

LED FLASHER ( About 1Year )

2010-08-31T00:19:00.000-07:00

This is so useful circuit diagram for you Because this circuit can light up an LED about 1 year with 9V battery.Here I have used famous IC HEF 4093.

Note

# Use a white colour LED

# Build this on a PCB to get maximum result

# Use 9V battery to power this circuit

9V (2A) power supply circuit diagram

2010-08-19T23:10:00.000-07:00

Lots of members asked about 9V dc power supply with 2A.So here We have introduce a new circuit diagram.This circuit can provide 9V 2A.I suppose now you all have some what good power supply with some what good amp level.This circuit operates with famous IC 7809.If I say simply this is a amp booster circuit.

Note

# Build this circuit on a PCB to get maximum result

# If you can attach a heat sink to the IC It will get a long life

Ding Dong Bell circuit diagram

2010-08-05T02:09:00.000-07:00

This is a ding dong bell circuit diagram.I have attached this circuit for my house.Even you can use this circuit as an sound generator.When we buy this circuit from the market we have to spend much money but now you can build this your self.Here I have used common Ic Ne 555 and you can operate this circuit with 9V power supply.

Note

# Build this circuit on a pcb

# use 9V power supply to power this circuit

# When you deal with 230V be careful

12V LED Flasher for Cars

2010-07-28T20:42:00.000-07:00

This is so wonderful circuit diagram Because you can up grade the out look of you car or van by using this simple circuit .Actually this is a blinking Led circuit on the other hand this circuit is called multivibrator circuit.The impotent thing of this circuit is this circuit can be operated with 12V power supply

Note

# By using R2, R3, C1 ,C2 you can change the speed of the circuit

# Fix this on a pcb

# Don't supply more than 12V

# This circuit can generate about 5W power

Simple ufo Detector Circuit Diagram

2010-07-27T21:49:00.000-07:00

This is some what different concept But here I have used very simple method.Most of people in the world find UFOs by looking at the sky most of time we can see some rich people buy cameras and focus them to the sky.But those unites are so expensive here I have shown you very simple diagram.When UFOs pass our area normally those machines out put high magnetic field so here we have used that magnetic power to detect them.when a UFO passes your area the magnet of your circuit will move. then the circuit will be switched on

Note

# Use 3V power supply

# Click this to make UM66 music circuit

Simple Water Level Detector

2010-07-27T02:22:00.001-07:00

This is so useful circuit diagram because this circuit helps us to detect water.When the water come and touch the sensors it will make a sound.Here I have used common transistor bc109. Actually you can modify this circuit.. By using a relay you can switch on or off your water motor I will tell you them in my next post.

Note

# Use 6V to power this circuit

# The distance between the circuit and the sensors should be short.

# Build this circuit on a pcb to get good result.

230V Blinking LED

2010-07-12T19:47:00.000-07:00

Already I have posted 230V LED circuit diagrams.This circuit is different than those circuits.Because this circuit is blinking circuit.And here I have used common parts so you all can find them easily.Already I have attached this circuit with our doorbell switch then the visitors who visit my place at night can see it well.

Note:-

# When you deal with 230V be careful because it is dangerous
# Fix this circuit in a plastic box

Simple Melody Generator Circuit Diagram

2010-06-11T09:31:00.000-07:00

This is so impotent circuit for you all.On the other hand this is so important circuit for beginners.Here I have used IC UM66 You can get various musics when you buy UM66 with different numbers.

Note:

# Don't supply more than 3V

# Build this circuit on a pcb