| ??? 07/09/09 05:14 Read: times |
#166893 - more details Responding to: ???'s previous message |
Kai Klaas said:
...give us some more details, please.
What currents are you talking about? Who generates the currents to be measured? How is that current generated? What range of currents? What precision? etc etc.. Ok, Current is generated by a constant current source, the source is stable enough for precision I need. I need precision of 0.1% of maximum load for each range. current range is between 100uA to 10A. for example for 1mA range I need 1uA resolution, for 10mA I need 10uA resolution and so forth. Kai Klaas said:
It depends. 1% resistors can give a drift of 0.3% in two years, when temperature at surface is high. In climates with long high temperature periods and high air humidity drift can be even higher. very interesting, where did you get 0.3% in two years? is it experimental or documented? Kai Klaas said:
Sometimes you can fabricate resistances by yourself, by the help of precision wire, especially low ohmic shunt resistors can be fabricated by this. Can I do better than ready made 0.1% wire resistors? |
