If i have current transformer which convert 300 amp to 1 amp ( 300 / 1 ) turn ratio . My secondary current varies between mili ampere up to 20 ampere ( maximum current and that happen when fault occur at High side cable )
I want to be able to read all these ranges of current between a few mili ampere up to 20 ampere and rectify them. The problem is ;-
1- at few mili ampere diodes used for rectification can not turned on ( because it needs 0.7 volt and that far away because i just have mili volt)
I reasearched and find a precision rectifier using op amp.
My quesion is can i use op amp even if my input signal is 0.0001 volt and rectify it ( i have this volt when i have few mA ) ?
Or this value is too low ?! I can not amplify it because some times i get 20 amper.
How to deal with this varing range ?
How can i solve this problem ?