# Zener voltage regulator circuit simulate this circuit – Schematic created using CircuitLab

I have here a voltage regulator circuit using a Zener diode.

We were tasked to find the maximum allowable $$\i_L\$$ given the varying voltage input so the the load voltage will remain at 8 V.

The way I understood the problem, we are asked to looked for $$\I_{z(max)}\$$ since past that, the Zener diode would no longer be able to maintain the voltage at 8 V. But then, I thought $$\I_{z(max)}\$$ is supposed to be given in a Zener diode's data sheet and also depends on the power rating of the diode (which was not given,) so I am unsure how to proceed with this problem.

• So, the zener is 8V but what is the power rating ??? Oct 9, 2020 at 8:03
• @GrahamStevenson It wasn't given. The quantities I mentioned in the post are the only ones given.
– user263783
Oct 9, 2020 at 8:09
• Lord Above ! Is there no end to daft question asked by lecturers. Would a classic 1.3W zener be OK ? Oct 9, 2020 at 8:11
• @GrahamStevenson I don't think so lol. They don't like us making assumptions with that stuff.
– user263783
Oct 9, 2020 at 8:15
• @Batt max zener power dissipation is at max input voltage 33V and zero load I.e. all current is flowing through zener Oct 9, 2020 at 9:45