I am new to arduino and I wanted to make an h-bridge because it is not easily available in india. I want to control the h-bridge using arduino uno r3 board and 2n2222A transistors and 1n4001 Diodes if necessary. I want this h-bridge to control two motors in a single direction. If possible pls include the friting diagram. I had created the circuit using NPN transistor and flyback diode and a resistor for both motors individually, I am posting the diagram , This is the link to the tutorialtutorial linkenter image description here

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    You don't need an H-bridge if your motors turn in a single direction, just one NPN, one resistor and one flywheel diode per motor. – Edgar Bonet Jun 23 '15 at 11:52
  • @EdgarBonet I used that setup but both motor wont start together – AadityaCool Jun 23 '15 at 12:04
  • @EdgarBonet only one motor works at a time in that case – AadityaCool Jun 23 '15 at 12:04
  • The you have a bug somewhere. Please post a schematic of your circuit and a minimal test sketch revealing the problem. – Edgar Bonet Jun 23 '15 at 12:07
  • @EdgarBonet okay will friting diagram do? – AadityaCool Jun 23 '15 at 12:08

I am posting this as an answer so I can show the diagram. But, my answer proper is in my comments above - your diagram is badly wrong. If what you have built is the same as the diagram then it is not what you are trying to build. And, if the diagram is wrong, you should fix it.

Fritzing can do an OK job of showing layouts when used well. But your diagram is unable to be interpreted with certainty. It is not a matter of you "not being good with Fritzing" as you say - it is a matter of putting in enough effort to show what you are trying to show. If it is wrong you MUST fix it - it is pointless to show people absolute rubbish which cannot be correct.

You say " ...I did exactly the same, [as the example]..." BUT your diagram and his are different and half your diagram cannot work in any way.

You MUST compare the two and not just keep pretending that yours and his diagrams are identical.

Look at the diagram below - copied from your diagram.
Inside the orange ellipse - how do the blue wire, green wire, diode and transistor really connect.
Why do your wires not end on "holes" in the breadboard - if a wire end is between two holes, which is it really meant to connect to?
Follow the red and blue lines that I have added to show current flow through one motor. The current MUST go THROUGH the diode in your example. In his example the motor current does NOT go through the diode. FWIW - your diodes can not pass current in the direction shown - but that's not your main problem. FIRST fix the wiring so it is the same as his and the same as what you have built/ THEN your main question may be able to be answered - or may answer itself.

LOOK at his diagram and yours.
Compare them.
Follow the current pars.
Realise that your one is wrong.

enter image description here

If you refuse to take advice and continue to insist that what you have shown on your diagram is the same as the example then you will be unhelpable. Or, take advice and learn as you go and you will find it a rewarding hobby.

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  • I am extremely sorry, for my mistake with the fritzing diagram. I was definitely not careful but let me assure you I have made the same as the tutorial. I created individual circuit for each. still the motors never work together – AadityaCool Jul 15 '15 at 15:56

It looks as if it may be the case that you are driving one transistor base from digital output #3 and the other from #11. (A circuit diagram, rather than a wiring picture, would allow one to better know the connection plan.) Instead drive both of the 220 Ω base resistors from one pin.

Regarding motor power, motors typically are ok with somewhat-unregulated DC. Supplying the motors with power that goes through the Arduino board's regulator may cause the regulator to run hot or may draw more current than the regulator or the USB connection is rated for. (A standard USB downstream port can deliver 500mA.)

You can test each of your motor circuits independently of the Arduino by connecting each base resistor to +5 or to ground (while the resistor isn't connected to Arduino).

You can hook each motor to a battery or to a 5 V power supply and measure its current consumption to find out how much current is needed.

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  • It does not seem to work – AadityaCool Jun 24 '15 at 7:14

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