circuit question-positive volrage input, zero voltage output

[tommydidi]

circuit question

Hey Guys,

I am going to design a circuit which should be able to achieve the following function:

If the voltage applied to this circuit is negative, exactly the same negative voltage should be sent to the output; If the voltage applied to the circuit is positive, zero voltage should be delivered instead.

Any thoughts?

Thanks

 

[strennor]

circuit question

A buffer with cliping.

with negative supply rail

 

[saro_k_82]

Re: circuit question

What you need is a negative half wave rectifier without the diode drop. Place the rectifying diode inside the opamp feedback loop to get around the diode drop problem.
https://en.wikipedia.org/wiki/Precision_rectifier