Let's assume the following circuit, where Zener diode is used as a voltage regulator. R16 (R18 later) is the load.
When the input voltage is sufficiently high for Zener diode to be reverse-biased, according to the current-voltage curve of the Zener diode, the current will flow through it. Also, I know that the resistance of the diode is very small (milliOhms) when it is opened.
Considering all of the above, I guess we can exchange the diode with the resistor of low resistance (R20 in the image below).
Now we can calculate the currents through R20
So, if the load has a small resistance, then most of the current will flow through Zener diode.
My questions are:
- Is it the correct interpretation of Zener diode's functioning?
- Do we use it for the loads, where only the voltage is important?