L293NE and arduino

So I want to make a simple avoiding robot with a sensor e.t.c. and I am facing some problems.I want to use a L293D but I took by mistake a L293NE.I read that the only diference between the two is that the L293D has the diodes attached and in L293NE you have to attach some diodes.I am using the arduino uno and I want to use 3v motor for a later robot but for now I want to use a motor that a car had already attached and it runs with a 6.0volts and is 650mAh.So maybe it is a stupid question but where and how do i put the diodes in the circuit and can I use( and if i can how do I) 3v motors somehow???

Thanks a lot !

Go to http://www.datasheetdir.com/L293+Motor-Controller-Drivers, look for the circuit labelled "L293 Application circuits".

This shows on the LHS a standard H-bridge with the flyback diodes, the RHS shows two motors driven in single-ended mode, but you can wire that side as an H-bridge too.

The diodes need to be able to handle pulses of the full load current of the motor.

Look at http://www.ti.com/lit/ds/symlink/l293d.pdf page 3 there you had the diodes, apply diodes to the other type, outside the circuit. This is flyback diodes who protects the circuit against voltage spikes from the motor. Perhaps not necessary but does't hurt.

Pelle

OK thanks for the reply but can i use a 3v motor or not ?and if yes the Vin how many volts must be?

orestman: OK thanks for the reply but can i use a 3v motor or not ?and if yes the Vin how many volts must be?

The datasheet tells you how many volts the high and low-side drivers lose for given currents, but a rule of thumb is 2 to 3V in total (two darlington stages, each loses between 1 and 1.5V)

The datashet tells you supply voltage range 4,5 - 36 volts, 3 volt are out of range

Voltage loss high side 1,4 V, low side 1,2 total 2,6 volts. With 5 volts in, the motor only gets 2.4 volts.

Pelle