Jonathan, this is pretty close, but could some clarification...

A zener diode IS a primitive voltage regulator. Normally, zener diodes are
wired in parallel with the load, and shunt excess current in order to "clamp"
the input voltage at the zener rating. The power supply voltage must be greater
than the zener diode's breakdown rating, and have a current-limiting resistor
wired in series with the zener diode and the load to drop the power supply
voltage to the zener's value. It's this shunted current, (oddly) called the
"zener current" BG that determines the wattage of the diode. So if you're
using the zener to clamp the voltage at 6V, the device draws 3 amps, and the
anticipated zener current is 0.5 amps, you'd need a zener diode rated for at
least 3 watts. (6V X 0.5A = 3W) Note too that a zener diode can't work if the
current through the limiting resistor causes the voltage at the top of the
zener diode to drop below its rated reverse-bias breakdown value. If this
happens, the zener current drops to 0 and whatever the voltage is at the
limiting resistor's junction with the zener diode is the voltage applied to the
load.

On the other hand a voltage regulator, for all practical purposes, IS the power
supply to the load, and its power rating is determined solely by the load
current. So if we have a 6V device that draws 3 amps, our 7806 voltage
regulator must be rated for at least 18 watts. You are correct in stating that
the voltage applied to the load device will always be 6V, regardless of the
current drawn by the load. (Ironically, the 78-series voltage regulator chips
use zener diode networks internally to provide their reference voltages.)

This link provides an excellent explanation of zener diodes and has schematics
of what I've tried to explain above:

http://hyperphysics.phy-astr.gsu.edu...ids/zener.html

HTH.

Respectfully,
Scotty

*** And now, we return to our regularly-scheduled program... ***

"Jonathan Ward" wrote:

solid state semiconductor regulator chip, in this case it

Dern it, I should have explained better.
Yes, it is an hourmeter. Round and made to fit in an instrument panel
hole approx 2 1/8 dia.
Nope, have no idea what the current draw is. How do I measure that?
Semi conductor chip....is this what is called a zener by someone else?

A zener diode and a voltage regulator are not the same. If you had a
zener diode rated at 6 volts for the avalanche point, then it is
guaranteed to have a voltage drop of 6 volts from lead to lead, if you
hook it up properly. Because of this when you hook it up in series like
the other guy described, 12-6 =6

The voltage regulator is the much more sophisticated way of doing it. If
you use one of those, the voltage will always be 6 volts no matter what.

The trouble with both parts is getting one big enough to handle the
current.

-Jonathan