12 V zener causes 1/2 volt too much?
Yay! I was pretty close predicting 11.65 V for the zener.
If you need to lose 1/2 volt, R1 only calculates to use up 1/2 volt at .05 amps.
Reducing R1 to zero would be necessary to trigger 1/2 volt sooner so that method won't work.
You're going to have to work with the zener to fine tune this.
If you can drop in an 11.5 volt zener, you're done.
If you can't get an 11.5 V zener, go lower and increase the output voltage by increasing the resistance of R1.
In other words, I'm with debe on this.
Yay! I was pretty close predicting 11.65 V for the zener.
If you need to lose 1/2 volt, R1 only calculates to use up 1/2 volt at .05 amps.
Reducing R1 to zero would be necessary to trigger 1/2 volt sooner so that method won't work.
You're going to have to work with the zener to fine tune this.
If you can drop in an 11.5 volt zener, you're done.
If you can't get an 11.5 V zener, go lower and increase the output voltage by increasing the resistance of R1.
In other words, I'm with debe on this.