DeadEnd Andamento Zener question.

[photon]

Hey guys,
I'm building the Andamento and it calls for a 7v Zener, which doesn't seem to be too common. I have a 6.8v and a 7.5v. Do you think either of those are close enough?

Thanks

[GibsonGM]

Can you post a schematic so we can see where the zener goes?   Welcome to the forum, BTW 

[photon]

Here you go:


Thanks

[antonis]

It's in series with LED status indicator so Vz isn't a big deal.. 

[photon]

Cool, thanks for the help. I appreciate it.

[GibsonGM]

Adonis, why did they do that?  It seems to be a waste of a part from my point of view.

[antonis]

Adonis,

( )

IMHO, there is no particular reason other than voltage reduction..
(and possibly LED overvoltage protection..)

[GibsonGM]

OVERKILL  That just cost everyone 15 US cents...

[PMowdes]

Adonis, why did they do that?  It seems to be a waste of a part from my point of view.

The zener is on the original circuit and we have just been true to the original design, it's there because i think you can run it on a battery and the zener gives you a pseudo low battery indicator.  It's easy enough to bridge the zener and not use it.

[antonis]

i think you can run it on a battery and the zener gives you a pseudo low battery indicator.

In such a case, LED would be OFF for effect both engaged and bypassed..

[digi2t]

Adonis, why did they do that?  It seems to be a waste of a part from my point of view.

The zener is on the original circuit and we have just been true to the original design, it's there because i think you can run it on a battery and the zener gives you a pseudo low battery indicator.  It's easy enough to bridge the zener and not use it.

Agreed. Just install a jumper across here and be done with it. It's what I've done with all the Last Gasp builds.

[Rob Strand]

A 7V zener seems too high.   By the time you add the voltage drop of the LED the unit will drop out on low battery very early.

Maybe a 5.1V or 5.6V would be better.

Ideally you would dial down the DC voltage until the unit misbehaved then choose a zener voltage which dims the LED at the right point.