L298N Works but Incorrect Input?

Thread Starter

Spankyty

Joined Jul 24, 2018
4
Hello, new to this site so sorry if anything is in the wrong spot. I have this L298N motor driver. I am using it to run my 5v stepper from my DVD/CD Drive. The thing is, I power the driver with 5v in the +5v input but then the motor does not run.. (I hear it struggling) I put the 5v into the +12 input and it works great!? So why does it do this? Is it safe? I don't want to damage my board.

I have also tested this with my external 5v supply and it does the same thing so it is not just the Arduino.

It seems like the +5v and the +12v silk label traces (I think that is what they're called) are opposite. Could it be they were labeled backward?

(I know you can have a 5v output if you're using >12v and take the jumper away.)

HAVE A LOOK AT THE VID
 

LesJones

Joined Jan 8, 2017
2,319
Your post does not make it clear if you are just using the L298 driver IC or if you are using a module that uses that device. Also you do not make it clear if you are talking about supply voltages or logic signal levels. Post a schematic of have you have it connected and the waveforms of the logic driver signals.

Les.
 

MrChips

Joined Oct 2, 2009
19,274
Presumably you are using an L298 module such as this one:

L298 Dual Motor Driver.jpg

The +5V Power terminal is not the supply input for the motor.
Use the +12V Power.

Note that on the internet, some sites show the +5V and +12V terminals interchanged. You will have to trace the wiring on the module in order to determine which is the correct power input.
 

Thread Starter

Spankyty

Joined Jul 24, 2018
4
Your post does not make it clear if you are just using the L298 driver IC or if you are using a module that uses that device. Also you do not make it clear if you are talking about supply voltages or logic signal levels. Post a schematic of have you have it connected and the waveforms of the logic driver signals.

Les.
I am using a module that uses the device. I am putting 5v into the +12v to power the supply voltages for the motors and the logic signals.

Presumably you are using an L298 module such as this one:

View attachment 184149

The +5V Power terminal is not the supply input for the motor.
Use the +12V Power.

Note that on the internet, some sites show the +5V and +12V terminals interchanged. You will have to trace the wiring on the module in order to determine which is the correct power input.
I traced the wiring and the +12v goes to the voltage source. I have successfully got one motor to work fine but then when I add another module and motor they lose torque and cannot move the sled.
 

MrChips

Joined Oct 2, 2009
19,274
Don't take the stuff you see on youtube for granted. A lot of what is posted is garbage.
Come here for clarification.

Why do I say this? A youtube video is one person's production and opinion.
On AAC, there are at least a dozen members reading the post, each with over 40 years experience in the field. Hence there is a peer review process on every post. We will easily catch the frauds.
 

KeithWalker

Joined Jul 10, 2017
413
https://lastminuteengineers.com/l298n-dc-stepper-driver-arduino-tutorial/

Ok, so to run my 5v motors I need 7v because of the voltage drop according to this link. So this must be my problem. I prefer youtube to learn this stuff so I don't get why no one really mentioned this. I should use websites more often lol.
Why didn't you simply check the data sheet for the L298 IC (attached). It specifies the sink and source saturation voltage at different currents.
https://www.sparkfun.com/datasheets/Robotics/L298_H_Bridge.pdf
 

Thread Starter

Spankyty

Joined Jul 24, 2018
4
Don't take the stuff you see on youtube for granted. A lot of what is posted is garbage.
Come here for clarification.

Why do I say this? A youtube video is one person's production and opinion.
On AAC, there are at least a dozen members reading the post, each with over 40 years experience in the field. Hence there is a peer review process on every post. We will easily catch the frauds.
Definitely will for now on. :D

Why didn't you simply check the data sheet for the L298 IC (attached). It specifies the sink and source saturation voltage at different currents.
https://www.sparkfun.com/datasheets/Robotics/L298_H_Bridge.pdf
I guess I didn't understand it the way they worded it. I'm sorry.
 
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