Don
I am building the circuit ...
Just to remind myself how much I dislike wire-wrap. Didn't mind it much at work with an electric wrap gun and pre-stripped wire ... this hand wrapping and stripping is a bit of a chore too far
Have now done a variant PCB with no wraps but a lot more links. Some you don't win, some you lose ....
You don't need limiter resistors if you set V
supply the same as the LED V
fwd, the current will the be very near to the nominal.
If you count up that piccy, there are 16 segments being driven.
The PSU output current draw is a shade over 170mA
ie. just over 10mA through each segment. Which is more or less what the data sheet says.
If I drop the output to 3.2V they extinguish. 1.6V is not enough to drive the LED ( each of the 2 per segment)
No need to believe me .... try it for yourself ..
Dave
Here you are, hang the expense .... snip from data sheet
Disregarding the decimal point, it says ( V
f ) ... Somewhere between 4V and 5V the current will be 20mA through each segment. I'm at 4.2V and about 11-ish mA. Well within the operating area.