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View Full Version : H-BRIDGE PROBLEM



snk_naveen
05-30-2009, 07:18 PM
hi friends,
i built a h bridge circuit i found on net here

http://library.solarbotics.net/circuits/driver_4varHbridge.html

and it works fine when it test it on breadboard there is no problems , but when i connect it to my MCU and ran it the transistors heats up very much now iam confused please help

vikas
05-30-2009, 09:01 PM
Check how much current its using , Whats the rating of your motors ? I hope u giving right inputs as this is a smokable hbridge !

debu
05-30-2009, 10:03 PM
@snk_naveen: Who ever said that it is a smokeless H-Bridge, lied. :p
What is the input voltage that you are giving to the transistor? Is it more then 5v? Also, I highly recommend an reverse EMF protection diode in this circuit. Secondly, avoid floating inputs to the h-bridge at all costs, so use pull-up's on the uC output pins.

Hope this helps,

Regards,

Debu :)

avinash_g
05-31-2009, 11:38 AM
Better use L293d IC

snk_naveen
05-31-2009, 11:42 AM
yes iam giving 5 volts and iam using a motor like this , that i found it in toys

http://robokits.co.in/shop/index.php?main_page=product_info&cPath=2&products_id=210&zenid=isljniubj2bs7oss25ottnf7p0

is the load in this motor too high for the transistors to take ??