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Aaru
03-03-2010, 03:21 PM
Hi... I'm using two L293NE ICs to control motors. I'm giving logic input in parallel to the two IC's. The 12V supply I'm using, for motor driving, has a current rating of 4.5AHr.Since the two L293s are in paralle,l will i hav to limit the current input to the Ics from battery? If so what resistance values should i use?


N whats the internal resistance of L293, my multimeter shows open circuit resistance.....Please do help me...The bot is for a racing competition. I'm using a remote kit from toy car to control..I already busted two l293s,..

rahuljin
03-04-2010, 01:26 AM
what is the current rating of motors ??

i think u can u a 7812 regulator for limiting the current to 1amp, if the current rating is low.

if the current rating of motor is high, go for l298.

pratheek
03-04-2010, 09:14 AM
You cannot limit the current going to the motors with a resistor, there will be a lot of power wastage and the resistor will get hot. You will have to use a resistor with a high power rating(not a viable option).

Whats the voltage and current limit you want to apply?

vikas
03-04-2010, 09:28 AM
L293 is rated for 1 A , What are the motors consuming ?

akshay66
03-04-2010, 02:06 PM
Go For L298.

Aaru
03-04-2010, 02:49 PM
Current rating of the motor is 1 ampere...
I want to limit the current input to the maximum power handling capacity of the IC...I tried using the same battery to drive 2 motors using a single L293 and succeeded.. But I dunno how long the IC can handle the current, especially when motor demands maximum current under worst cases..
Can anyone tell me if there are any disadvantages in using L298???

vikas
03-04-2010, 02:59 PM
Drive the L293 using PWM.

L298 is lil more expensive , requires external diodes and is hard to solder ... other wise ill recommend is from the start.

Aaru
03-04-2010, 03:19 PM
I'm using a ready made remote kit to control...What value of current sensing resistor should i use for L298(terminals 1 and 15)....

Aaru
03-04-2010, 05:15 PM
Is current sensing circuit a must when using L298 circuit.if not can i ground 1 and 15 directly

pratheek
03-05-2010, 01:58 PM
Current rating of the motor is 1 ampere...
I want to limit the current input to the maximum power handling capacity of the IC...I tried using the same battery to drive 2 motors using a single L293 and succeeded.. But I dunno how long the IC can handle the current, especially when motor demands maximum current under worst cases..

L293NE can handle 1 Amp. Add a heat sink to the IC to be safe.

If you are still not able to drive the motors, then you can solder another L293NE on top of the existing one. You will be connecting them in parallel by doing so and you can drive motors upto 2 Amps.