Is the Zener shown backwards in this circuit if zener is being used as voltage regulator?

Thread Starter

harryec

Joined May 5, 2018
6
I thought the zener effect was when the current went threw the diode reverse direction. In this diagram it looks to me like the current would be going in forward direction... hence no zener effect. Or... am I reading the symbol incorrectly. Thanks for your kind help. Sorry for asking such silly questions.. but I'm just learning this stuff...trying to get it straight in my head.

upload_2018-5-6_10-32-18.png
 

Audioguru

Joined Dec 20, 2007
11,248
The forward or reverse direction of a zener diode depends on the polarity of the input voltage. But your input voltage has no polarity shown.
 

Thread Starter

harryec

Joined May 5, 2018
6
The forward or reverse direction of a zener diode depends on the polarity of the input voltage. But your input voltage has no polarity shown.
Ah... so if no polarity is specified... you could draw it either way... and it would be correct because the way you drew the zener would pretty much specify the polarity that would be required IF the zener was acting as a voltage regulator via the zener effect.

Thanks!
 

WBahn

Joined Mar 31, 2012
29,976
Hello,

As drawn in the schematic in post#1, the input voltage will be positive.
Since no reference polarity is provided, what does a "positive" input voltage mean? We can't (well, shouldn't) just assume that the bottom node is the 0 V reference. It almost certainly is, but it is a bad habit to not identify it as such -- sooner or later someone will get bit because they will be working with a circuit that is not properly annotated and they will assume the obvious and the obvious will be wrong.
 
Top