how to find the gain response of LM358

Thread Starter

andhavarapu lokesh

Joined Aug 17, 2017
46
I want to amplify lower voltages from ranging from (0.3millivolts to 133millivolts ) using LM358P can anyone tell me how to find the gain response of the LM358
 

Thread Starter

andhavarapu lokesh

Joined Aug 17, 2017
46
It means that device has max input offset of 2mV and you cannot input signals lower than 2mV to it and it is not a Rail-To-Rail output OpAmp.
sir i am not getting the gain uniform if i vary from 3milli volt to 133mv whats happening means it is giving maximum gain around 31db at 3mv output voltage is also negative . But when it goes around 1.5 output voltage sign changes gain also reduced 17db and then onwards gain increases from 23-30.9
 

Thread Starter

andhavarapu lokesh

Joined Aug 17, 2017
46
It means that device has max input offset of 2mV and you cannot input signals lower than 2mV to it and it is not a Rail-To-Rail output OpAmp.
sir i am not getting the gain uniform if i vary from 3milli volt to 133mv whats happening means it is giving maximum gain around 31db at 3mv output voltage is also negative . But when it goes around 1.5 output voltage sign changes gain also reduced 17db and then onwards gain increases from 23-30.9
 

jayanthd

Joined Jul 4, 2015
902
sir i am not getting the gain uniform if i vary from 3milli volt to 133mv whats happening means it is giving maximum gain around 31db at 3mv output voltage is also negative . But when it goes around 1.5 output voltage sign changes gain also reduced 17db and then onwards gain increases from 23-30.9
Show your exact hardware circuit. What power supplies are you using ?

I have not use LTSpice. I use Proteus.

I checked the datasheet. It says Max input offset voltage is 5mV.
 
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Thread Starter

andhavarapu lokesh

Joined Aug 17, 2017
46
hi,
Yes, download it from the Yahoo LTS user group.
Is this sim showing the non linearity, the circuit will be non linear, what is the frequency of your input signal.?

E
i am not giving any ac i am giving Input dc voltage to non inverting teriminal from 0.003 to 133 millivolts thats it
 

ericgibbs

Joined Jan 29, 2010
8,878
hi,
I assume you are talking about a real LM358 circuit.?
What is the source of the 3mV to 133mV signal.?
E
EDIT:
This is the LM358.mod, change the LM358mod.txt to LM358.mod
 

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