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How do you amplify 0.2V to 2.5V using op-amp?

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eastsheen

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Hi! How do you amplify 0.2V to 2.5V using op-amp? It will be much more appreciated if there was calculations involved. Thanks
 

How to use op-amp?

Use it as an amplifier with gain set to 12.5.

Calculation is very simple Vout = Gain * Vin.

Gain calculation will depend on which configuration you choose. Search for amplifier using op-amp on web and you will find plenty of options.
 

Re: How to use op-amp?

Calculation depends on the design or the IC chip you have chosen. The datasheet may provide the formula. For general op-amp, you can search in the web for amplifier op-amp. The formula are usually there. Try search inventing op-amp or non-inverting op-amp.
 

Re: How to use op-amp?

For a gain of 12.5 you must use a nin inverting configuration:

12.5 = 1+R2/R1
11.5 = R2/R1
R2 = 11R1

if R1 = 10kΩ then R2 = 110kΩ
 

Re: How to use op-amp?

Miguel,
somehow the ".5" disappeared from your calculations. Shouldn't that be 11.5? This would make the resistor R2=115k for R1=10k. Actually, one could use a potentiometer to better tune the output to the desired voltage.

Best regards,
v_c
 

Re: How to use op-amp?

Hi Friend,

Operational Amplifier is an IC.
It has two modes.
* Inverting mode
* Non Inverting mode
For the derivation of the calculations refer "Ramakant A Gayawad" "Op Amps and Linear Integrated Circuits" Prentice Hall of India Publications.


Regards,
Avinash.S.

Added after 3 minutes:

Hi dipal_z,

The formula that u've given is only for the Inverting mode. Please give me the formula for the Non inverting mode also.

Thanking you,


Regards,
Avinash.S.
 

How to use op-amp?

Hi,
There are two kinds of amplifier using op-amp_ DC and AC amplifier, here you need DC amplifier, this is different from AC amplifier. You should be careful when design a board.
 

Re: How to use op-amp?

Don´t be confused: In principle, there is no difference between dc and ac amplification using opams.
The only difference could be if you use single supply operation, because in this case a decoupling cap is to be used which blocks dc.
LvW
 

How to use op-amp?

Hi,
There are two kinds of amplifier using op-amp_ DC and AC amplifier, here you need DC amplifier, this is different from AC amplifier. You should be careful when design a board.
 

Re: How to use op-amp?

please check my result if it is right:

for inverting amplifier:
Vo = -Vi(Rf/Ri)
2.5 = -0.5(Rf/Ri)
5 = - (Rf/Ri) equation

for non-inverting amplifier:
Vo = Vin[1+(Rf/Ri)]
2.5 = 0.5[1+(Rf/Ri)]
5 = 1+(Rf/Ri)
4 = Rf/Ri equation

please evaluate the solution

regards
randell_xtian :D:D:D:D
 

Re: How to use op-amp?

Yes, of course it is OK.

Here are the equations to be applied in general:

1.) Inverter: Vin to be applied to Ri and the + opamp terminal grounded:
v=-Rf/Ri

2.) Non-Inverter: Vin to be applied to the + opamp terminal and Ri grounded:
v=+(1+Rf/Ri)
 

Re: How to use op-amp?

i think my solution is right becoz LvW op-amp formulas are also i used. [/quote]
 

Re: How to use op-amp?

As I have stated on May 22:
In principle, there is no difference between dc and ac amplification using opamps.
The only difference could be if you use single supply operation, because in this case a decoupling cap is to be used which blocks dc.
 

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