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pratik123
06-01-2005, 10:47 PM
As i have already asked sme ppl the motor doesnt run using normal op amps etc due to low current...I saw somewhere we need to run a motor using power transistor can sme1 explain to me how dis is done pls..

Or can it be directly operated using L293D connected to PC parallel port??
I wud think even in this case the current wont be enuff

ice
06-01-2005, 11:10 PM
or can it be directly operated using L293D connected to PC parallel port??

The l293d has its own separate supplywith it's ground shorted to the parallel port ground....hence it sources voltage and current,to the motor, from its own supply.
If you refer the L293D datasheet,it can source a max of 600mA.Thats enough for your motor.

It does work..people have done it,including me : )..soyou neednt worry

pratik123
06-02-2005, 12:29 AM
Well thanks for that..Ur earlier mail put me on the track but i was jus slighlty worried since the L293D costs 90 bucks and i didnt wannt to wreck it
But i'll try n tell u again thanks again though

dhruvkaran
06-02-2005, 09:38 AM
i tried it, its not working
i am getting ony 2.37 v and 55 mA across the l293d
l293d works properly as expected acc. to the prog
the adapter is supplying >200mA
but as soon as i connect the motor, BANG!!, the voltage drops to 0.2V
and obviously,the motor doesn't work at 0.2V/55mA
please help
dhruv

vidur
06-02-2005, 09:49 AM
2.37V?????

What r using for powering up the l293d

if you're using a PM-DC motor, the voltage drop to 0.2V should not matter as long as the current does not drop....remember the transistor is essentially a current source


However check if your power supply voltage doesnt drop to 0.2 V
if it does, that probably means that you gotta use a higher power supply..

dhruvkaran
06-02-2005, 12:18 PM
What r using for powering up the l293d
well we are using a variable power source(local adapter) 1.5 to 12V DC and 500 mA.(max) source




However check if your power supply voltage doesnt drop to 0.2 V
if it does, that probably means that you gotta use a higher power supply..

i checked it, the power supply is stable at around 13V(varies from 12.7V to 13.2V depending on whether the port is giving 0x01, etc.)

what should i do next. please help. both of us are very keen to learn more and this is slowing it down

awaiting help
dhruv

ps:WHATS A PM-DC motor

vidur
06-02-2005, 02:21 PM
check your motor

does it run if you connect it directly to say ...a 5V source

if not....email me a copy of your ckt diagram...
vidur_itm@yahoo.com

Oh ya.....one more thing
PM-DC =perm. magnet DC motor

ice
06-02-2005, 04:45 PM
Could you post your wiring diagram,with the L293D and motor corrections..

You may be going wrong in your connections...
The 293D is rugged..i have mine since 4 years,tried to blow it,..never succeded

pratik123
06-02-2005, 05:09 PM
Well the diagram was taken from ur parallel port tutorial as far as i kno..
But i will tell dhruv to put up the exact diag he assembled

dhruvkaran
06-03-2005, 04:06 PM
we've mailed u the ckt diag.
do see it and let us know of our mistakes
dhruv

dhruvkaran
06-04-2005, 11:15 AM
hey all u fundoo's out there
come on please help us further(why is this forum stuck)
we are newbies and u ppl are the only way out of this for us and we look up to all u ppl
i got the ic changed and still it is not working
please please help, this is a very bad situation , we are stuck on a very basic thing since 4 days
dhruv

yogi
09-16-2005, 01:55 PM
when u r touching the heat sink of the power transistor, be careful

don't touch with ur full finger, first test it is heat or not then u remove transistor from bread board or so


Bibin John
www.bibinjohn.tk

addy
10-10-2005, 07:15 PM
short pin no. 1,8and 16 to +5v
short pin no. 4,5,12 and 13 to gnd.
connect motor to pin no. 3 and 6 ang give logic inputs to pin 2 and 7.give 12 v to pin 8.
its an active low driver.

addy
12-24-2005, 02:38 AM
use the transistor with a heat sink... if u wanna save it from blowing up.