Why is the reverse biased zener diode used for voltage regulation?
The curve is much more useful in the reverse breakdown mode. Especially for avalanche diodes, which every &quot;Zener&quot; diode over above 5V actually is.



simulate this circuit &ndash; Schematic created using CircuitLab
Here I have swept the current from 100uA to 100mA on each type of &quot;regulator&quot; diode.
Compare the regulation of each:

Temperature coefficient is also ~4x better, about +6.5mV/°C vs. roughly -25mV/°C