I just wanted to make sure I didn't miss something about this.
Series diodes don't work as well as Zeners but they are useful (dV/dI is higher) and your suggestion for this application is a good one.
Another trick is the reverse biased emitter to base junction of a silicon transistor can be used as a "poor man's Zener" with a voltage drop of 5 volts or so. Just don't exceed the dissipation rating.
Neil
I really want to thank you guys for your
comments.
I have been a ham since 1971 and have had
a lot of fun. But this Part 15 stuff has made
me think about electronics problems that I
have never thought of before.
I think I'll get a bunch of 1N4001s, drag out
the old variable bench supply and do some
experiments.
I also thought of trying to run the 49 MHz link
receiver at less than it's design voltage - say -
8, instead of 9 volts. The receiver will then need
less energy. However, that will require more 1N4001s.
So I don't know if the total energy required at 8 volts will
be reduced significantly.
I know nothing about solar cells. These cells are supposed
to supply 6 volts at 50 mA. But maybe they don't in the
wintertime, when the sun is low on the horizon and the
visible rays have to go through more of the Earth's
atmosphere. Maybe under those conditions, do the solar
cells provide less current?
My funds here are limited, because of my ongoing medical
(eye) situation. But I think when I can, I'll have to make
an "artificial sun." A couple of 100 watt light bulbs stuck
on top of a box I think would be helpful.
I'm going to go back and read your comments again. I
just wanted to reply while I had the chance.
Best Wishes,
Bruce, MICRO1690/1700
I really want to thank you guys for your
comments.
I have been a ham since 1971 and have had
a lot of fun. But this Part 15 stuff has made
me think about electronics problems that I
have never thought of before.
I think I'll get a bunch of 1N4001s, drag out
the old variable bench supply and do some
experiments.
I also thought of trying to run the 49 MHz link
receiver at less than it's design voltage - say -
8, instead of 9 volts. The receiver will then need
less energy. However, that will require more 1N4001s.
So I don't know if the total energy required at 8 volts will
be reduced significantly.
I know nothing about solar cells. These cells are supposed
to supply 6 volts at 50 mA. But maybe they don't in the
wintertime, when the sun is low on the horizon and the
visible rays have to go through more of the Earth's
atmosphere. Maybe under those conditions, do the solar
cells provide less current?
My funds here are limited, because of my ongoing medical
(eye) situation. But I think when I can, I'll have to make
an "artificial sun." A couple of 100 watt light bulbs stuck
on top of a box I think would be helpful.
I'm going to go back and read your comments again. I
just wanted to reply while I had the chance.
Best Wishes,
Bruce, MICRO1690/1700
3 pin voltage regulators are also cheap. Most will work with a minimum input/output differential of about 2 volts. Since you will be dropping 3 to 4 volts it should work.
You can use a 7805 regulator and make it adjustable by adding a voltage divider between the output pin-ground pin and ground connection.
This trick works by raising the ground pin voltage which in turn raises the output voltage. Keeping the voltage divider current as small as practical will minimize losses there. Of course overall the regulator will probably use more power than the simple diode network.
Since the ground pin current is fairly constant, the new output voltage is nearly as constant as the 7805 is designed to be.
3 pin voltage regulators are also cheap. Most will work with a minimum input/output differential of about 2 volts. Since you will be dropping 3 to 4 volts it should work.
You can use a 7805 regulator and make it adjustable by adding a voltage divider between the output pin-ground pin and ground connection.
This trick works by raising the ground pin voltage which in turn raises the output voltage. Keeping the voltage divider current as small as practical will minimize losses there. Of course overall the regulator will probably use more power than the simple diode network.
Since the ground pin current is fairly constant, the new output voltage is nearly as constant as the 7805 is designed to be.
TESLA has developed something new and important in the way of storage batteries for getting off the grid:
http://inhabitat.com/new-tesla-battery-could-take-your-home-off-the-grid/