## Change inverting low pass into non-inverting with only 1 op amp SOLVED

 In this question I figured out how to make a op amp filter with 1kHz lowpass and gain of 10, but it's actually -10 because its inverting: How can I make it non-inverting +10 gain without adding another opamp? THanks by CAMIE538 November 15, 2016

 Copy+pasted berniekorries and then moved the capacitor around and added $R_3$. You want to separate the gain and the low-pass because otherwise they mess each other up. I made them separate by putting the frequency filter on the non-inverting input side, and by putting the gain on the output / inverting input side of the circuit. Click it, run the frequency sim, you'll see it works as promised: ACCEPTED +2 votes by carrolllip86 November 15, 2016 Nice. Good enough for me. Can it be done without adding another resistor? by CAMIE538 November 15, 2016

 How about this? I changed $R_2$ to $9k\Omega$ and moved it all around so the capacitor is on the output. −2 votes by berniekorrie November 15, 2016 This is wrong!!! Run your simulation and you'll see. It does have gain +10 and it does start to roll off at 1kHz. BUT it also starts to flatten out at 10kHz. So probably not what you're looking for. by carrolllip86 November 15, 2016 At "low frequencies" the capacitor C1 looks like an open circuit, so the whole thing just looks like a standard gain of +10 non-inverting amplifier. But at "high frequencies" the capacitor looks like a short circuit, which shorts out R2. Now the whole thing just looks like a gain of +1 non-inverting buffer. That's NOT how a low pass filter should act. by carrolllip86 November 15, 2016 Good catch, my mistake. by berniekorrie November 15, 2016

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