Easy 6v From Regulated 12v Supply
 

There's a simple voltage reducing trick that Drake used in at least one model
of an emergency marine receiver. To make the 12-volt powered receiver operate
on ships with 24 volts (Europe), a Zener diode was put in series with the d.c.
input. It was installed inside the cabinet, which had plenty of room. Because
of the current requirement, it was a hefty top hat type.

That could be done for civilian SW units, to operate off readily available
regulated 12-volt power supplies. I recall that, after a couple of Zener
failures in customers' receivers, we installed two or three smaller values in
series instead of a single 12-volt Zener.

So, for a 6-volt/500 ma (1/2 amp) receiver like my DX-392, I would use, say,
three 2-volt/1 amp Zeners in series between the power supply output and the
power input to my receiver.

Bill, K5BY

Cool,
What runs on 6v's now days?

WShoots1 wrote:
There's a simple voltage reducing trick that Drake used in at least one model
of an emergency marine receiver. To make the 12-volt powered receiver operate
on ships with 24 volts (Europe), a Zener diode was put in series with the d.c.
input. It was installed inside the cabinet, which had plenty of room. Because
of the current requirement, it was a hefty top hat type.

That could be done for civilian SW units, to operate off readily available
regulated 12-volt power supplies. I recall that, after a couple of Zener
failures in customers' receivers, we installed two or three smaller values in
series instead of a single 12-volt Zener.

So, for a 6-volt/500 ma (1/2 amp) receiver like my DX-392, I would use, say,
three 2-volt/1 amp Zeners in series between the power supply output and the
power input to my receiver.

Bill, K5BY

A LOT of stuff runs on 6 volts (4 "AA") batteries these days. But if you
choose to run a zener diode in series you lose any regulation you might have
had. If a car is charging it's battery correctly it will be at 13.8 to
14.2Volts. Six volts worth of drop would yield 14.2V- 6V=8volts! NOT a good
way to go.
A better way to go is to use a 7808 (they do exist,but a 7806 does not) and
place two 1N4001 diodes in series on its output. 8Volts-1.4v(diode
drop)=6.6volts. DO NOT float the ground ref on the 7808 as the tempeture
charactoristics of the diodes will come into play.If you decide to go this
route, remember to place a 10Mfd AND a .1Mfd fliter close to the 7808 to
prevent it's possibility of generating any noise.
If you MUST use a "Zener" type regulator, Motorola does make a family of
them rated at 50 watts in a TO-3 style case..Eddie

"Burr" wrote in message
link.net...
Cool,
What runs on 6v's now days?

WShoots1 wrote:
There's a simple voltage reducing trick that Drake used in at least one
model
of an emergency marine receiver. To make the 12-volt powered receiver
operate
on ships with 24 volts (Europe), a Zener diode was put in series with
the d.c.
input. It was installed inside the cabinet, which had plenty of room.
Because
of the current requirement, it was a hefty top hat type.

That could be done for civilian SW units, to operate off readily
available
regulated 12-volt power supplies. I recall that, after a couple of Zener
failures in customers' receivers, we installed two or three smaller
values in
series instead of a single 12-volt Zener.

So, for a 6-volt/500 ma (1/2 amp) receiver like my DX-392, I would use,
say,
three 2-volt/1 amp Zeners in series between the power supply output and
the
power input to my receiver.

Bill, K5BY

7806's do exist. (I'm looking at one right now.)
LM7806 or 78M06. Easy 6VDC.
Data Sheet:
http://www.htckorea.co.kr/data/LM78XX.pdf

Probably the best solution would be an LM317
and two resistors forming a voltage divider to set
the output voltage. One could use a single trimpot
as well. Then you could set any voltage you want.
Don't forget to use bypass caps on the input and output,
and a heatsink.