Hello,
How do I figure out what the (SMD) resister code/value of my A4988 drivers are?
I bought some of these. Amazon.com.
I am trying to figure out if I should be looking at R1, R2 or R3 on the driver.
Thanks
Post a clear, focused picture of the top view of your board.
In the photos posted on Amazon, the two labeled R100 are 0.1 Ohm, and are almost certainly the current sense resistors.
And that is consistent with what to expect on the Chinese clone drivers.
The HR4988 is a Chinese imitation of the Allegro A4988, so you should check the data sheet.
The formula for setting the current limit may not be the same as for the Allegro chip.
"so you should check the data sheet",
I tried to find the data sheet for it but haven't been able to. I Googled that brand of driver but didn't find any specs on it. Is there a way to get the specs on it?
I did an internet search for "HR4988 datasheet", and the first hit turned up a large number of them.
The only one I looked at was in Chinese, with English language labels on the drawings that they copied directly from the Allegro data sheet.
I see what you mean about the data sheets.
For right now I will go with " the two labeled R100 are 0.1 Ohm, and are almost certainly the current sense resistors.".
Thanks
I use the formula:
Vref = 8 * Imax * Rs (Rs = 0.1 for my Chinese clones marked R100)
from the Pololu A4988 page with success.
Thanks for all the help everyone.
I am trying to use that Vref formula that's why I was trying to find out about the specs of my HR4988 drivers.
That Pololu page is really helpful.
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