Kendrick:
For a voltage divider I use a 10k 20 turn screw trimpot. I set the pot to 20 to1 approx 500ohm to 9k5. I tried fixed through hole resistors and it took 30seconds or more for the number to settle, I don’t have the equipment to try SMD resistors.
The voltage value settles immediately with the pot do you recon I have too low a pot and should have chosen a 100k pot?
Kendrick
Hmm, a pot is not the way to do this - too much scope for mechanical creep changing the ratio, and
10k is too small a value, you're getting self-heating and maybe electrolytic effects on the wiper
contact point.
Use precision fixed resistors, 1% or better, don't use carbon(*), use metal film. Use resistor values that will
not self-heat appreachably - so 220k/10k perhaps. That's only 45mW or so (only a few degrees temperature
rise, not 10's of degrees)
(*) The tempco of carbon resistors is shocking, not suitable for measurement applications.