How to convert 120v AC to 1.5V DC?

I have an outdoor solar light with automatic photo sensor which
operates with single 1.5v AAA battery. I want to connect the solar
light to 120v outlet so it can stay on all the time at dark. Can
anyone tell me what kind of options I might have to do this
conversion? Thank you in advance for your help.

 

[Ted Pavlic]

On Sep 17, 3:50 pm, nase...@gmail.com wrote:

I have an outdoor solar light with automatic photo sensor which
operates with single 1.5v AAA battery. I want to connect the solar
light to 120v outlet so it can stay on all the time at dark. Can
anyone tell me what kind of options I might have to do this
conversion? Thank you in advance for your help.

There are several canned products that can do exactly what you need. A
quick Google search for "1.5V DC transformer" leads me to this
"battery eliminator:"

http://www.testpath.com/Items/DC-Power-Supply-Battery-Eliminator-15V-or-3V-3A-122-014.htm

All of these products will use a transformer internally to step-down
the 120V to some lower level. They'll then use a rectifier to keep the
voltage positive, and then they'll use some signal conditioning
circuit (often a linear regulator IC) and some large output buffering
capacitors to hold the output constant. Here's a more do-it-yourself
example:

http://www.awrr.com/1point5voltPS.html

That example is nice because it uses an LM317, which in that package
can give you 1A of output current --- plenty for your use.

 

[Jamie]

naser41@gmail.com wrote:

I have an outdoor solar light with automatic photo sensor which
operates with single 1.5v AAA battery. I want to connect the solar
light to 120v outlet so it can stay on all the time at dark. Can
anyone tell me what kind of options I might have to do this
conversion? Thank you in advance for your help.
Go buy your self a wallwart.

they make universal types that will select down to
that low of voltage.


http://webpages.charter.net/jamie_5"

 

[ehsjr]

naser41@gmail.com wrote:

I have an outdoor solar light with automatic photo sensor which
operates with single 1.5v AAA battery. I want to connect the solar
light to 120v outlet so it can stay on all the time at dark. Can
anyone tell me what kind of options I might have to do this
conversion? Thank you in advance for your help.

Get cat # DCTX-5200 from Allelectronics
http://www.allelectronics.com/make-a-store/item/DCTX-5200/5-VDC-2000-MA-WALL-TRANSFORMER/-/1.html
(watch for line wrap in the above)

Put 6 1N4001 diodes in series with the 5 volt DC output
and the solar light. That will drop the voltage delivered
to the light down to about 1.4 volts.

Ed

 

[Dave, I can't do that]

On Sep 17, 12:50 pm, nase...@gmail.com wrote:

Can anyone tell me what kind of options I might have to do this

Shine a light on the solar cell and put black tape over the sensor.
<grin> OK, just sorta kidding.

Go here...
http://www.allelectronics.com/make-a-store/category/815200/Wall-Transformers/D.C.-Wall/1.html

Get one of the 3v ones and use a resistor in series. The "light" will
be an LED which will almost certainly have a resistor already in
series to limit current. Someone here smarter than me can tell you
what value for the resistor.

Dave

 

[Charlie Siegrist]

On Wed, 17 Sep 2008 13:08:05 -0700 (PDT), Ted Pavlic
<ted.pavlic@gmail.com> wrote:

On Sep 17, 3:50 pm, nase...@gmail.com wrote:
I have an outdoor solar light with automatic photo sensor which
operates with single 1.5v AAA battery. I want to connect the solar
light to 120v outlet so it can stay on all the time at dark. Can
anyone tell me what kind of options I might have to do this
conversion? Thank you in advance for your help.

There are several canned products that can do exactly what you need. A
quick Google search for "1.5V DC transformer" leads me to this
"battery eliminator:"

http://www.testpath.com/Items/DC-Power-Supply-Battery-Eliminator-15V-or-3V-3A-122-014.htm

All of these products will use a transformer internally to step-down
the 120V to some lower level. They'll then use a rectifier to keep the
voltage positive, and then they'll use some signal conditioning
circuit (often a linear regulator IC) and some large output buffering
capacitors to hold the output constant. Here's a more do-it-yourself
example:

http://www.awrr.com/1point5voltPS.html

That example is nice because it uses an LM317, which in that package
can give you 1A of output current --- plenty for your use.

Excellent answer. I will add that OP should find a way to make the
installation suitible for outdoor use, some sort of sealed plastic
enclosure. I turned up this page after a quick search:

http://www.pactecenclosures.com/

 

[Jasen Betts]

On 2008-09-17, naser41@gmail.com <naser41@gmail.com> wrote:

I have an outdoor solar light with automatic photo sensor which
operates with single 1.5v AAA battery. I want to connect the solar
light to 120v outlet so it can stay on all the time at dark. Can
anyone tell me what kind of options I might have to do this
conversion? Thank you in advance for your help.

easist is to merely replace the battery:
you need a way to get 1.5v from 120V
and, if you want it lit during the day, some black paint over the photo sensor
except it's probably not a 1.5V battery (more likely 1.25V or 1.2V)

it may be simpler to disconnect the LED from the rest of the circuit and power that
from a higer voltage with an apropriate dropping resistor. (eg use a 5v wall wart
and a 68 ohm resistor)

Bye.
Jasen