Hacking a Resistor to 100.00% accuracy
Which 10KΩ Resistor would you choose :-
Well to tell the truth its the same one ..... just the one below has been Tweaked !
The Trick is to file the body of the resistor (beneath the outer shell _ into the carbon/metal) using a needle file (or cosmetic/nail file).
Most common resistors are made from Carbon/Metal film or metal oxide, by file_ing the Carbon/Metal away the resistance can be tuned to whatever value you want.
Basic rule :- The resistance increases with file_ing.
Resistance = Length of resistor / cross section Area x (substance conductivity)
The Bare facts ........ the shell removed reveals how the manufactures also mill/file the surface to trim (did i dig out an industrial hush-hush)
Resister values are are quoted @20°C ..... and fluctuations of the resistance can occur due to external environment.
If you make excessive deep cuts then the power rating of the resistor will also suffer.....
Do not adjust the Resistor on live equipment....... (risk of shock)
How many times have you hacked a servo to continuous servo and added the two resistors to replace the potentiometer...... only to find that when you send a center (1500) command to the servo ....it creeps....creeps...creeps albeit slowly but it nerves the heck out of you.... and you have to put software jigs to stop the motor from creeping......well look no further just get the file out and tune away........(leaving your code perfect)
Or.... your trim pot is just to coarse to balance a circuit ..... place a cheaper resistor in and file it too suit......
....enjoy ...... comments and likes are appreciated........... other ideas/uses even more soo...