Steve Kosmerchock said:

> +0.6V to +1.2V (voltage is variable) as input, I need an op-amp  to give
> me an output swing of +10V (when input is +0.6V) to +0.3V (when input is
> +1.2V).
>
> Would you then figure out the gain of the circuit then use an offset as
> needed, if so how would you figure out how you find what offset is
> needed?

Gain is -16.1666 based on the .6 volt input change to -9.7 volt output
swing, i.e. -9.7/.6

Offset is calculated by finding the voltage at the center of the two gain
resistors. Remember the voltage is the same on both inputs of an opamp
when it's operating linearly. And the inputs draw no current.
Pick a known state, say when the input is 1.2 volts and the output is .3
volts.
The voltage difference is .9 volts
The voltage at the center of the divider is 1.2 - (1/(1 + 16.1666)) * .9 =
1.148 volts
Put that into the non-inverting input.

Cheers,

Bob

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