Now if I may ask you a question, where do you want to use mosfet in linear region....can you share the schematic please??hi crutschow,
I haven't had yet a chance to dive into op amps, but Q1
seems to be what would work for me. The exponential relation
complicates things. But if I may ask you a question
how does the op amp attenuate the voltage's input's
amplitude so that it makes the MOSFET linear ....???
Also, can I use an Lm324 as opposed to an OPA333?
I should really put some time in testing op amps !!!
anyways thanks so much for your help.
The op amp doesn't really make the MOSFET linear, but it does make the output versus input linear as stated by #12. It uses negative feedback to make the non-linearity very small (basically divided by the open loop gain of the op amp).................
seems to be what would work for me. The exponential relation
complicates things. But if I may ask you a question
how does the op amp attenuate the voltage's input's
amplitude so that it makes the MOSFET linear ....???
Also, can I use an Lm324 as opposed to an OPA333?
...................
After all the schematics i have posted and worked outNow if I may ask you a question, where do you want to use mosfet in linear region....can you share the schematic please??
Very well explained #12. This gives me at least an ideaThe basic concept of an opamp is that it does whatever is necessary to make both of its inputs equal. The opamp is responding to the voltage from the potentiometer and providing whatever is required to get its other input to the same voltage. In this case, the opamp is changing the voltage on the gate of the mosfet just enough to get it to pass enough current to get the right voltage across the load resistor.
okay.... thanks so much for your circuit... really appreciatedThe op amp doesn't really make the MOSFET linear, but it does make the output versus input linear as stated by #12. It uses negative feedback to make the non-linearity very small (basically divided by the open loop gain of the op amp).
Yes, an LM324 should work for this purpose.