# Preliminary project

#### darif

Joined May 27, 2018
5
Hello, I am looking for a circuit that transforms sin (wt) into cos (wt) and cos (wt) into sin (wt). I tried to use a direvator or integrator circuit but both changes the sign of sin or cos. in other words I'm looking to turn (wt) into (-wt + pi / 2). Thank you.

#### Alec_t

Joined Sep 17, 2013
13,229
Welcome to AAC!
An integrator or differentiator should work. If the polarity needs changing you can add a unity-gain inverting stage.

#### darif

Joined May 27, 2018
5

#### darif

Joined May 27, 2018
5
Welcome to AAC!
An integrator or differentiator should work. If the polarity needs changing you can add a unity-gain inverting stage.
I have taken a differentiator circuit and I have found the following problem: I do not have to add a unity-gain inverting stage unless my signal is a cos and not for a sin

#### darif

Joined May 27, 2018
5
I will ask my question differently. If I find a circuit that changes the sign of the signal phase it will help me to solve my problem:
sin(ωt)----->sin(-ωt).
Attention: I want to change the sign inside the sinus function, i do not want to get it out of function
Thank you

#### ArakelTheDragon

Joined Nov 18, 2016
1,353
I will ask my question differently. If I find a circuit that changes the sign of the signal phase it will help me to solve my problem:
sin(ωt)----->sin(-ωt).
Attention: I want to change the sign inside the sinus function, i do not want to get it out of function
Thank you
The upper option (unity gain buffer) does exactly that. There is not much difference between sin and cos.

#### -live wire-

Joined Dec 22, 2017
956
I have an ingenious circuit for getting wt to wt+pi. Flip the wires around.

#### Alec_t

Joined Sep 17, 2013
13,229
Why do you want to change one into the other? Knowing the context here may point to a suitable solution.

#### darif

Joined May 27, 2018
5
Why do you want to change one into the other? Knowing the context here may point to a suitable solution.
a- for sin(-wt) we have two steps: wt-------->(-wt) and -wt-------->sin(-wt)
b- for -sin(wt) we have two steps too: wt-------->sin(wt) and sin(wt)------->-sin(wt)=sin(wt+PI)
if I use b Iwill change the phase ((-wt) into sin(wt+PI)) , but for my project I will kept the phase in (-wt)
then I want use the case b