Opamp - Non inverting Amplifier

[rpisharody]

Hi,

The other day, I was doing an experiment involving the Fairchild 741C opamp. I had designed a simple Non inverting amplifier with input resistance 1K and feedback resistance 10K.

Now, when I switched on the circuit(the gain I expected was 10), the value of gain went upto 25 and stayed there in that range. But when the frequency of input was varied to about 1MHz, the gain dropped as expected.

I checked the resistances, changed it(but kept the values same. I needed the answer for why), but the gain still stayed in that range. Now from the equation of the non-inverting amplifier, these are the values of resistances to be used.

Then why did it show anomalous results ? Any idea?

 

[kronos2k3]

Hi... Please check te resistors values, the correct connection of the circuit, or change the 741!
The teorical gain is G=(R2/R1)+1; because is a non inverting amplifier, then G=(10K/1K)+1=11!

Best regards from Argentina!

 

[rpisharody]

Thanks for your advice.
But thats exactly what I did. I checked the connection and the resistors.
The only thing left is the opamp itself. I'll check it and report back on Monday

 

[rpisharody]

It was a problem with the opmap. When I replaced it, everything worked fine.
Thanks for the response