Electronic – the advantage of non-inverting op amp high pass filter

filteroperational-amplifier

The non-inverting op amp high-pass filter (first picture below) has a unity gain limit close to DC, while inverting op amp high-pass filter (second picture below) doesn't have such a limit. So why do people still use the non-inverting high-pass configuration?

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Best Answer

There is a reason non-inverting 1st order high-pass filters are sometimes used and this is to preserve the dc level in the circuit. It's horses for courses - some designs will want to preserve the DC level, some won't care and some won't want to. It's not a black and white sort of thing.

When it comes to a 2nd order high-pass filter the non-inverting configuration (Sallen Key type) will usually be preferred and this doesn't preserve the dc level: -

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Again horses for courses.