Another fluorescent nightlight dissected

[James Sweet]

http://picasaweb.google.com/lh/photo/vZDkQ8cEjsiEV6QAyGspMQ?feat=directlink

This cute little First Alert nightlight someone gave me a while back
lasted all of 6 hours before it failed. The lamp is a small U-shaped hot
cathode fluorescent made of tubing roughly 11mm diameter. R3 was burned
beyond recognition but measured around 32K which may or may not be close
to its original value and both cathodes in the lamp are open. All
resistors are 1/4W except for R2 which appears to be a 1/2W fusible type.

D1, D2, C1, and C2 form a half wave bridge voltage doubler. R1 and R5
discharge the capacitors when the unit is unplugged. R2 serves as the
ballast, limiting current in the tube, while R3 and R4 provide current
to heat the cathodes. Running the tube from DC can't be good for it
under the best of circumstances but I would hope these typically last
longer than this one did.

 

[Dr. Heywood R. Floyd]

This cute little First Alert nightlight someone gave me a while back
lasted all of 6 hours before it failed. The lamp is a small U-shaped hot
cathode fluorescent made of tubing roughly 11mm diameter.

Just another electro-greenless dope looking for yet another meaningless
way to dump electrons through wires?

If you don't have kids, you don't need a night light. Even with kids,
it can be argued against.

Carry an LED flashlight around that you keep by your bedside, or simply
with you in your dark house at night. They do not consume much, and you
can get the lever charging type.

Even a monkey knows how to familiarize himself with his local domain...
even in the dark.

Also, learning how to walk blindly in known surroundings exercises the
brain, and you learn a skill as well.

It also adds safety, as in if there is a fire, the smoke makes it pitch
black, even with a night light, so the skill of 'knowing' one's floor
layout is actually an essential safety measure.

 

[Archimedes' Lever]

This cute little First Alert nightlight

I particularly like how you (if you drew it) placed a Positive indicator
on the AC power source. That was funny.

It looks like a very wasteful way to light a CFL. For a few pennies
more, they could have lit the lamp with less power being consumed. That
looks very inefficient.

 

[Rich.]

http://picasaweb.google.com/lh/photo/vZDkQ8cEjsiEV6QAyGspMQ?feat=directlink

This cute little First Alert nightlight someone gave me a while back
lasted all of 6 hours before it failed. The lamp is a small U-shaped hot
cathode fluorescent made of tubing roughly 11mm diameter. R3 was burned
beyond recognition but measured around 32K which may or may not be close
to its original value and both cathodes in the lamp are open. All
resistors are 1/4W except for R2 which appears to be a 1/2W fusible type.

D1, D2, C1, and C2 form a half wave bridge voltage doubler. R1 and R5
discharge the capacitors when the unit is unplugged. R2 serves as the
ballast, limiting current in the tube, while R3 and R4 provide current to
heat the cathodes. Running the tube from DC can't be good for it under the
best of circumstances but I would hope these typically last longer than
this one did.

There's those mysterious diodes again.

 

[James Sweet]

There's those mysterious diodes again.

What's mysterious about them? The purpose is obvious in this circuit,
the diodes are part of a voltage doubler.

 

[Kirk Johnson]

http://picasaweb.google.com/lh/photo/vZDkQ8cEjsiEV6QAyGspMQ?feat=directlink

This cute little First Alert nightlight someone gave me a while back
lasted all of 6 hours before it failed. The lamp is a small U-shaped hot
cathode fluorescent made of tubing roughly 11mm diameter. R3 was burned
beyond recognition but measured around 32K which may or may not be close
to its original value and both cathodes in the lamp are open. All
resistors are 1/4W except for R2 which appears to be a 1/2W fusible type.

D1, D2, C1, and C2 form a half wave bridge voltage doubler. R1 and R5
discharge the capacitors when the unit is unplugged. R2 serves as the
ballast, limiting current in the tube, while R3 and R4 provide current to
heat the cathodes. Running the tube from DC can't be good for it under the
best of circumstances but I would hope these typically last longer than
this one did.

I am Curly Gouger Watts (The Anal Man) & I come from down your way.

Kirk Johnson
"Anal Stretching Specialist"
http://www.imagefap.com/image.php?id=1988478267

 

[Lynn]

http://picasaweb.google.com/lh/photo/vZDkQ8cEjsiEV6QAyGspMQ?feat=directlink

This cute little First Alert nightlight someone gave me a while back
lasted all of 6 hours before it failed. The lamp is a small U-shaped hot
cathode fluorescent made of tubing roughly 11mm diameter. R3 was burned
beyond recognition but measured around 32K which may or may not be close
to its original value and both cathodes in the lamp are open. All
resistors are 1/4W except for R2 which appears to be a 1/2W fusible type.

D1, D2, C1, and C2 form a half wave bridge voltage doubler. R1 and R5
discharge the capacitors when the unit is unplugged. R2 serves as the
ballast, limiting current in the tube, while R3 and R4 provide current to
heat the cathodes. Running the tube from DC can't be good for it under the
best of circumstances but I would hope these typically last longer than
this one did.

now you know why someone gave it to you

 

[Curtis Brown]

now you know why someone gave it to you

why don't you shut your ass up you fucking ****?

 

[Archimedes' Lever]

It's "half right," right?

From a feedback perspective?

 

[James Sweet]

It's "half right," right?

The + was placed automatically by the CAD program, rather than bother to
delete it, I used it to indicate hot. Not sure why someone would bother
to nitpick a "back of a napkin" schematic I drew up just for fun though.
Curiously, as wired, the light has the switch on neutral, not that it
really matters given the whole thing is enclosed.

 

[russ]

The + sign should indicate the "Hot" wire on an single phase AC circuit.
The other side being the neutral. "H" would be better but is not always
available.