So i'm using the l293D motor driver. The problem i'm facing here
is when I connect the 9v battery to the whole circuit one of the
motor spins slow and the other spins slight faster.
Actually i want to make a robot and I'm using this circuit as a part of it.
I changed the 9v battery with a new one but nothing happened.
The motors are of 3v each.
Pls help guys.

 

without a schematic of your circuit, helping will be mostly guess work.

some troubleshooting checks to get you started. Motor or Driver? swap out your two motors and find out if the problem moves with the motor or is related to a driver output side.

 

without a schematic of your circuit, helping will be mostly guess work.

some troubleshooting checks to get you started. Motor or Driver? swap out your two motors and find out if the problem moves with the motor or is related to a driver output side.

I interchanged the motor and the output pins but no luck
I also tried another L293D but nothing happened
(I attached a fritzing image file)

 

Do you have proper schematics those fritzing renders are not exactly easy to read.

Measure the voltage on motor power lines and report back.(If you can measure it).

 

I interchanged the motor and the output pins but no luck
I also tried another L293D but nothing happened

What do you mean "no luck" and "nothing happened"?
Did the problem follow the motor when you changed things or not?

A 9V battery will not operate a two motors for very long. For a 3V motor you could use a couple of AA or larger cells.

 

Do you have proper schematics those fritzing renders are not exactly easy to read.

Measure the voltage on motor power lines and report back.(If you can measure it).

i checked. its 2.5v 0n one motor and 1.8 on the other.

 

Something is dropping the voltage,get a 9V adapter and use that.Battery will drain too fast.

Wire it like this:

 

Does the problem persist if you hardwire the enable/control lines on the L293D?

 

Change to 9V alkaline battery or using two 1.5V alkaline batteries in series.

 

Something is dropping the voltage,get a 9V adapter and use that.Battery will drain too fast.

Wire it like this:

Using a 9v adapter solves the problem.........

 

Change to 9V alkaline battery or using two 1.5V alkaline batteries in series.

this works too
thanks

 

Using a 9v adapter solves the problem.........

That just proved the 9V can't work properly for motor, and it can't give you the really working test for a robot.

 

What power source will the robot have?

 

The 2x2 GND pins in the middle of chip are used as heatsink connection to the PCB.So you should have something better then wires connected to them.

 

The 2x2 GND pins in the middle of chip are used as heatsink connection to the PCB.So you should have something better then wires connected to them.

can you suggest something...??

 

What power source will the robot have?

4 AA cells

 

can you suggest something...??

You could take 1.5x1.5 cm Alu/Copper sheet and drill 2 holes and solder the wires to 2 holes.