Zener/resistor or regulator

[Eugeneo]

In certain applications where power consumption and tight regulation is not a concern, does anyone use a 5.1v zener/resitor as a means to regulate power to a pic? I know it's really not a good way to regulate power since the minimum power is always wasted. For a very simple application, i've asked myself this, is it wrong?

[SherpaDoug]

They still sell millions of Zeners each year. They are cheap and simple to use. You sound like you are aware of their limitations, so count the pennies, count the Watts and the numbers will tell you the answer.
_________________
The search for better is endless. Instead simply find very good and get the job done.

[asmallri]

[SherpaDoug]

A lot depends on your definition of cheap. Are you building one space probe, or 500,000 winking teddy bears? You get all sorts comming to this BBS. I would rather tell them how to make a decision than to make it for them.
_________________
The search for better is endless. Instead simply find very good and get the job done.

[iso9001]

[dbotkin]

Another reason to consider Zeners in some applications: Assume you have a PIC device that is powered from either an internal battery (3 or 4.5 V) or an external power supply (3-12 V). A Zener will regulate the external supply but won't drain the internal battery. Most cheap regulators have an obnoxiously high Iq.

[arunb]

Hi,

A zener diode combinatio and transistor combinations are a a googd choise when you do not know the maximum curent drawn by the PIC (or other devices connected to the +5 V line).

These combinations do not burnt easily, on the other hand I have always faced problems with LM7805 regulators these tend to burnt out easily on a short circuit.

Well in any case it depends on the application you are designing.

thanks
arunb