[SOLVED] Noninverting Opamp Configuration for Gain Less Than 1

[hshah8970]

Hello everyone.

The gain for a regular noninverting opamp configuration is [ 1 + ( R_f / R_i )] .

This means that the output voltage will always be greater than or equal to the input voltage. But can we have a noninverting opamp configuration in which the gain is between zero and unity i.e. output voltage is lesser than the input voltage.

If figures will help, use the following ones:

An input voltage of +12 V. Desired output voltage of +6 V (half of input voltage). Positive and negative supply voltages provided to the opamp are +15 V and 0 V / ground.

 

[Syncopator]

No, you can't use the normal non-inverting configuration like that.

What you can do is use a voltage follower preceded by an attenuator.

If the input impedance of a resistive attenuator is too low, then use two voltage followers. One to which you connect your input voltage, then the attenuator and then another follower.

 

[hshah8970]

Thank you for your response.

I'm assuming this [ http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/spniatn.gif ] is the circuit you are referring to.

 

[Syncopator]

Yes, that's it basically.