[sdiy] makeshift 3v zener?

[nicolas]

Blue or white LEDs are usually about 3.5V but there is quite a bit of variation between different brands and batches.  Red LEDs are usually about 1.5V so two in series would do the trick - again sorting through a few batches might be necessary.  Green LEDs are often about 2V, so with one or two 1N4148s in series would also give you about 3V.  Using the forward voltage drop of a diode or LED is more current dependant than using a zener.

But if you are wanting the zener for its noise generating properties none of the above will work as all the forward diode type voltage refs are much quieter than the reverse type.

Remember also that if you are back-to-backing them in an AC situation to clip the signal, zeners go in series (pointing oppositely) and clip at their rated voltage plus 0.6V whereas LEDs go in parallel (pointing oppositely) and clip at their normal forard voltage drop.

Cheers,
Nicolas


--- On Wed, 25/3/09, René Schmitz <uzs159 at uni-bonn.de> wrote:


From: René Schmitz <uzs159 at uni-bonn.de>
Subject: Re: [sdiy] makeshift 3v zener?
To: "Dan Snazelle" <subjectivity at hotmail.com>
Cc: synth-diy at dropmix.xs4all.nl
Received: Wednesday, 25 March, 2009, 9:54 AM


Dan Snazelle schrieb:
> 
> can i make a 3v zener out of a higher voltage zener (3..9) or out of lower volt diodes?

LEDs might work instead of a zener. Green or perhaps even Blue ones. Maybe with some 4148s in series. Leds have a sharper knee than a string of diodes. (although low voltage zeners often have a soft knee anyway.)

Cheers,
René

-- uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



      Stay connected to the people that matter most with a smarter inbox. Take a look http://au.docs.yahoo.com/mail/smarterinbox