If you have a schmitt trigger completely designed for inverting, how would you go about inverting that signal?

I'm under the impression you can't just swap the input voltage to the V+ op amp input as that would completely mess up the calculations.

Thanks for the help.

 

Connect a second inverting Schmitt trigger to the output of the first.

 

I'm under the impression you can't just swap the input voltage to the V+ op amp input as that would completely mess up the calculations.

Depends upon the circuit.
Show us the circuit and we'll give a better answer.

 

Are you talking about an opamp or analog comparator circuit? If so, your impression is correct. You must know the output impedance of the signal source, because that impedance will be part of the hysteresis calculations.

ak

 

See

 

See

 

Connect a second inverting Schmitt trigger to the output of the first.

Pretty much - the same applies with logic device Schmidt. AFAIK: on the discrete transistor variety - you just use the other collector.

 

Connect a second inverting Schmitt trigger to the output of the first.

Does the second comparator need to be a Schmitt trigger?

 

Does the second comparator need to be a Schmitt trigger?

Maybe I misunderstood the question.
I was thinking that maybe TS had a 74LS14-style hex Schmitt triggers and just needed a non-inverting output.

 

Maybe I misunderstood the question. I was thinking that maybe TS had a 74LS14-style hex Schmitt triggers and just needed a non-inverting output.

I'm under the impression you can't just swap the input voltage to the V+ op amp input

... from the V- opamp input.

He has an opamp configured as a comparator with hysteresis. The signal of interest is connected to the inverting input, and either a reference voltage with a buildout resistor or a 2-resistor voltage divider tied to the non-inverting input. He calls this "a schmitt trigger completely designed for inverting", and wants a non-inverting equivalent; that is, one where the output goes high when the input signal is greater than the reference.

ak

 

Does the second comparator need to be a Schmitt trigger?

Only if the first one is really crappy.