As I understand it a 3.3v zener diode is supposed to not conduct any current in the reverse direction (like a normal diode). But as soon as a 3.3v or higher voltage is applied to it reversely, it will "open up" and start to conduct in the reverse direction.
But that's not what happens with my circuit:
Here I'm raising the input voltage from 0 volts to 10 volts.
What I expect to measure at the "measurement point" is:
As long as the input voltage is below 3.3v the voltage at the "measurement point" should be 0. But as soon as the input voltage reached 3.3v the zener diode should open and the voltage at the "measurement point" should be equal to the input voltage (minus diode drop maybe?).
But what actually happens is:
This is a small chart of the relationship between the input voltage and the voltage at the "measurement point"
Input Voltage --- Voltage @ Measurement Point
2v --- 0.06v
3v --- 0.5v
3.5v --- 0.9v
4v --- 1.2v
5v --- 2v
6v --- 2.8v
7v --- 3.8v
8v --- 4.7v
9v --- 5.6v
10v --- 6.5v
As you can see the diode doesn't have a specific voltage where it opens up. It almost linearly passes current and nothing specific happens at 3.3v even tho it's a 3.3v zener.
Can someone explain why I'm missing here?
Edit: What I'm trying to achieve is a voltage detector. I want the output to be LOW when the input voltage is below 3.3v and HIGH when the input voltage is above 3.3v