View Full Version : heat sink

12-10-2004, 10:56 PM
hi ppl
I am using a L293D for inferfacing my bipolar stepper motor to the current and current to the motor from o/p pins of L293D is around 450ma so it wll get heat up very fast so i need 2 use a heat sink....can u guys suggest me some types of heat sink dat i can use....what abt SL100????actully i m a bit confused as to how 2 incule it in circuit.....pls help me out by suggesting me some way....

12-11-2004, 08:29 AM
actually per channel current output of the L293d is 600mA.

Just take ur IC to the shop and ask him for a heat sink for a 16pin DIP..That should do it..
why arent u using a ULN2803 or a ULN2003 for running a stepper...
Connecting it is much easier..


12-11-2004, 09:59 AM
You can also use Heat Sink Paste ... Cause sometime there is aproblem in heat transfer ... It hhas worked wonders in my case sometimes . Also a small fan will be a nice addon .

12-11-2004, 05:58 PM
if one L29xd doesnt do the job with heatsink, use two L29xd in parallel.
SL100 wont be able to take that much heat either.
if you need to make the H-bridges with transistors, then go for TIP122, TIP125

he is doing the right thing using L29xD because he says his motor is "bipolar" stepper motor.

ULN2xxx series is good for unipolar stepper motors which are commonly available and which we like to use coz of the ease in hardware.

I guess i have some short explanation on my webpages on how to control a bipolar using l29x on trikiboard.


12-12-2004, 09:49 AM
he is doing the right thing using L29xD because he says his motor is "bipolar" stepper motor.
Thanks for clarifying


03-10-2005, 06:53 PM
I dunno if TIPXX series is cheap or expensive...if they are expensive....& you wish to use something cheaper

build a darlington pair out of A BC548 & an SL 100....i saw an EFY magazine ckt using it to drive a 1W-8 ohm load!....Even I've used it but for lower loads..& it doesnt heat up!

The Darlington pair is driven by the BC548 transistor!

03-12-2005, 09:52 AM
i suggest processer heat sink.its fins r long enough and if needed u can use fan.use thermal paste for better conduction.or drill a small hole and fix ur voltage regulator.
(look around old scrap computers for haet sink)


03-12-2005, 10:01 AM
Hey....I was reading L293's data sheet...it says that The ground pins ( all 4 of them ) are to be used for heat sinking......

You can tie all 4 pins to a thick metal wire & tie it to a small chunk of roughened aluminium....That'll work i guess!

03-25-2005, 09:50 PM
i wanna interface stepper motor to parallel port of PC .
& wanna control thrugh keyboard . plz help me for interfacing CKt &
C program .
mail me at jagsy_21@yahoo.com

12-31-2005, 01:19 AM
use uln2803 driver ic and send the bit patterns through the port.