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[SOLVED] Op-Amp Buffer using OP07 - Is it enough?

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Anantha Krishna

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Hi All,

I have a DC voltage output varying from -10V to +10V. I need an unity gain buffer which can Increase the Fan-out of this output. I thought of using OP07 as Op-amp buffer.

I have attached the circuit. Please check and confirm if any changes to be made.

Thank you.



76_1317470974.png
 

alexan_e said:
No he is not, this is a unity gain buffer, why should he use positive feedback?
Or you mean something different?

Alex
Click to expand...

for the buffer Vout mus be equal to Vin
in the above case gain =Vout/Vin=-Rf/Ri
Rf=feedback resistance=0(short circuited)
Ri=input resistance=infinate(open ckted)
so there is zero gain
now if you consider a non inverting amplifier as in my case
gain=1+Rf/Ri=1
hence Vout=Vin
 

Are you suggesting that the output will be inverted compared to the input because this is not the case.

Alex
 

srikanth1555 said:
for the buffer Vout mus be equal to Vin
in the above case gain =Vout/Vin=-Rf/Ri
Rf=feedback resistance=0(short circuited)
Ri=input resistance=infinate(open ckted)
so there is zero gain
now if you consider a non inverting amplifier as in my case
gain=1+Rf/Ri=1
hence Vout=Vin
Click to expand...

Srikanth,

may I recommend something to you?
Before answering questions like this you should try to become familiar with opamp circuits.
 
I need an unity gain buffer which can Increase the Fan-out of this output.
Click to expand...
Depends on the output load. Did you check the datasheet?
 

For this range of DC such buffer is totally ok. That is if you power it from standard +/- 15V source. It has extraordinary offset voltage for that price as well as external offset adjustment capability. It has low bandwidth, but that's a good feature for buffering dc signals, since it's lowers it's chance to oscillate randomly because of noise (which often becomes a problem when using high frequency opamps).

Generally it's a good practice to use decoupling capacitors of 100nF physically near the opamp power pins. This may improve opamps noise performance while the capacitors cost next to nothing.
 
To Poorchava,

Should I connect the bypass capacitors on both input and output side? Can you give a simple circuit connected with these bypass capcitors?
 

Bypass capacitors connect to the supply pins, not in- or output.
 

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