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| Fake Bourns 10 Turn Potentiometer Tested to Failure |
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| Nusa:
Replace yourself in the shaft-twiddling business...use a small stepper motor to turn the shaft at a human-like rate. |
| xavier60:
I had 3 of these fake Bourns 10 turn pots fail each with about 1 month's worth of heavy use as controls on a bench supply. When the resistance wire breaks, the pot behaves like a switch, no reference voltage when the wiper is below the break and full reference voltage when the wiper is moved above the break. This causes the PSUs output to jump from 0V to the full 30V without any warning, nasty! So far I have had no failures with the Bochen(WXD3-13-2W) 10 turn pots. I also added protection to detect abrupt increases in wiper voltage. |
| Nominal Animal:
A testbench with a bunch of 28BYJ-48 geared steppers with 3D-printed "shafts" for turning the pots, each pot configured in a voltage divider configuration with output to the controlling microcontroller ADC, and you could keep track of the linearity and turning noise as well. These steppers can run from 5V using a trivial ULN2003 unipolar driver, and are unlikely to lose any steps in this scenario. It'd be an interesting quick project for someone needing to test a bunch of pots. Me, I prefer to use encoders instead; I just like them more. |
| Refrigerator:
--- Quote from: Nominal Animal on June 14, 2020, 06:08:53 pm ---A testbench with a bunch of 28BYJ-48 geared steppers with 3D-printed "shafts" for turning the pots, each pot configured in a voltage divider configuration with output to the controlling microcontroller ADC, and you could keep track of the linearity and turning noise as well. These steppers can run from 5V using a trivial ULN2003 unipolar driver, and are unlikely to lose any steps in this scenario. It'd be an interesting quick project for someone needing to test a bunch of pots. Me, I prefer to use encoders instead; I just like them more. --- End quote --- 28BYJ-48 steppers are pretty slow, for something like this just about any stepper would work. |
| Nominal Animal:
--- Quote from: Refrigerator on June 14, 2020, 08:14:53 pm ---28BYJ-48 steppers are pretty slow, for something like this just about any stepper would work. --- End quote --- Sure, but the 28BYJ-48 are cheap (~ 15€ for a dozen), low-power, and ubiquitous. If you use a 32-bit microcontroller, you can pulse them fast enough to mimic human finger turning, methinks. |
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