Go Down

Topic: Using capacitors with the L293DNE H-bridge (Read 124 times) previous topic - next topic

Huntechr1

Hi everyone! I am planning to use the L293DNE H-bridge in order to control 2 DC motors. I watched a tutorial online which showed the basic setup for using this IC however, the guy said in order to do the proper setup it would be necessary to use capacitors. So my question is would it really be necessary to do this and if so where would they go? I will post the link to the video below and my wiring setup is the same as his, the only difference is that I would e using a 9 volt battery to power the motors.


https://www.youtube.com/watch?v=5nDaHJqruq0

DuaneDegn

#1
Dec 31, 2015, 10:41 am Last Edit: Dec 31, 2015, 10:42 am by DuaneDegn
the guy said in order to do the proper setup it would be necessary to use capacitors. So my question is would it really be necessary to do this and if so where would they go?
Yes, you want to use a decoupling capacitor on the Vcc2 pin (pin #8). One lead of the cap connects with Vcc2 and the other lead of the cap connects to ground. You want to keep the wires between Vcc2 and the cap as short as practical so trim the long leads of the cap so they're short.

A 0.1uF ceramic cap is pretty standard for ICs and I'm guessing it would be a good value for this application.

the only difference is that I would e using a 9 volt battery to power the motors.
9V batteries belong in smoke detectors not powering motors. I strongly suggest you use a different power supply.

The motor supply connects with Vcc1 (pin #16). The motor supply ground and the Arduino ground need to be connected together. Don't let the motor current pass through the Arduino. Connect the motor's ground close to the h-bridge not to the Arduino.

MarkT

The motor supply (as opposed to the logic supply) benefits from big decoupling (1000uF or similar).
Especially if the supply is weak and can't supply stall current.  Decoupling the supply also reduces
EMI radiated from the battery connections.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

DuaneDegn

The motor supply (as opposed to the logic supply) benefits from big decoupling (1000uF or similar).
Especially if the supply is weak and can't supply stall current.  Decoupling the supply also reduces
EMI radiated from the battery connections.
Do the motor caps need a higher voltage rating normal? Would half again as much as the motor voltage be enough for motor caps?



Huntechr1

Quote
I strongly suggest you use a different power supply.
What kind of battery would you suggest I use?

MarkT

Capacitors need to be rated at least as high as the maximum voltage they will see - but you are probably
right to allow a generous overhead since a decelerating motor can back-power the motor supply.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy