In article , Stepan
Novotill wrote:

A diode, ballast, or capacitor in series with each lamp would be

That would have been the proper solution. There are these little
buttons you stick to the tip of the screw-base of the bulb.

You then screw this entire thing into the socket. It's called a "bulb
saver" and is essentially a tiny diode in series that chops the
voltage across the bulb in half.

I assume the bulb bases for these exit lights are much smaller than
Edison based household bulbs (intermediate base perhaps?) and the
bulb savers I've seen are only for Edison sockets.

I think some EXIT lamp manufacturers were also selling LED retrofit
kits for some of these lights.

Also, door slamming and vibration could have been a partial reason for
premature lamp failure.

But now we're getting WAAYYYYYY off topic here.

--
Sven Weil
New York City, U.S.A.

On Wed, 03 Sep 2003 02:28:32 GMT, the renowned (Sven
Franklyn Weil) wrote:

You then screw this entire thing into the socket. It's called a "bulb
saver" and is essentially a tiny diode in series that chops the
voltage across the bulb in half.
snip

The RMS voltage across the bulb is reduced by ~29%.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

In article ,
mentioned...
On Wed, 03 Sep 2003 02:28:32 GMT, the renowned (Sven
Franklyn Weil) wrote:

You then screw this entire thing into the socket. It's called a "bulb
saver" and is essentially a tiny diode in series that chops the
voltage across the bulb in half.
snip

The RMS voltage across the bulb is reduced by ~29%.

Ooh, DejaVu, I think we've had this discussion before...

The bulb savers that I used back in the '70s were varistors. They
slowed down the turn-on of the light. They were low resistance when
warm, and high when cold. There was no diode.

Best regards,
Spehro Pefhany


--
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On Wed, 3 Sep 2003 03:31:59 -0700, the renowned Watson A.Name - "Watt
Sun" wrote:

In article ,
mentioned...
On Wed, 03 Sep 2003 02:28:32 GMT, the renowned (Sven
Franklyn Weil) wrote:

You then screw this entire thing into the socket. It's called a "bulb
saver" and is essentially a tiny diode in series that chops the
voltage across the bulb in half.
snip

The RMS voltage across the bulb is reduced by ~29%.

Ooh, DejaVu, I think we've had this discussion before...

It's like the UL about pulsing LEDs to get more brightness, it just
keeps coming around.

The bulb savers that I used back in the '70s were varistors. They
slowed down the turn-on of the light. They were low resistance when
warm, and high when cold. There was no diode.

I've seen the diodes, not the varistors. But I have no doubt you're
right. Probably very similar to the inrush limiters used on PC power
supplies, minus the leads.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Wed, 3 Sep 2003 03:31:59 -0700, the renowned Watson A.Name - "Watt
Sun" wrote:

In article ,
mentioned...
On Wed, 03 Sep 2003 02:28:32 GMT, the renowned (Sven
Franklyn Weil) wrote:

You then screw this entire thing into the socket. It's called a "bulb
saver" and is essentially a tiny diode in series that chops the
voltage across the bulb in half.
snip

The RMS voltage across the bulb is reduced by ~29%.

Ooh, DejaVu, I think we've had this discussion before...

It's like the UL about pulsing LEDs to get more brightness, it just
keeps coming around.

The bulb savers that I used back in the '70s were varistors. They
slowed down the turn-on of the light. They were low resistance when
warm, and high when cold. There was no diode.

I've seen the diodes, not the varistors. But I have no doubt you're
right. Probably very similar to the inrush limiters used on PC power
supplies, minus the leads.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Wed, 3 Sep 2003 03:31:59 -0700, Watson A.Name - "Watt Sun"
wrote:

The bulb savers that I used back in the '70s were varistors. They
slowed down the turn-on of the light. They were low resistance when
warm, and high when cold. There was no diode.

These were actually Metal Oxide NTC thermistors back then (not Metal
Oxide Varistors), since silicon diodes were at that time just a
curiosity in the "ELECTRICAL" world as opposed to the "ELECTROMICS"
world. The problem with the Diode or the NTC solution, is that it does
nothing to save the bulb from line transients.

I have seen actual VARISTORS being used for current regulation as
opposed to surge suppression (clipping), but only in old telephone
sets. I'm not shure of the principle behind this since a MOV is not a
temperature sensitive device, and am curious if anyone can explain.

A ballast based voltage drop, has better potential in that regard when
combined with a VARISTOR and fuse for surge suppression. So for an
extra $50.00 you get to keep your bulb longer. Hmm.

Stepan

Stepan Novotill wrote:

On Wed, 3 Sep 2003 03:31:59 -0700, Watson A.Name - "Watt Sun"
wrote:


The bulb savers that I used back in the '70s were varistors. They
slowed down the turn-on of the light. They were low resistance when
warm, and high when cold. There was no diode.


These were actually Metal Oxide NTC thermistors back then (not Metal
Oxide Varistors), since silicon diodes were at that time just a
curiosity in the "ELECTRICAL" world as opposed to the "ELECTROMICS"
world.

I think you have that backwards. Back then, the radio and TV sets were
still using 5U4 TOOBS for rectifiers, whereas the electrical world
already had equipment with SCRs up to the size of hockey pucks that
could handle up to 1200 amps (http://www.cehco.com/sda.htm), and 1N1184
series of 35 amp stud mount rectifiers were common in equipment
(http://dkc3.digikey.com/PDF/T032/0547.pdf). And your average battery
charger had diodes in it, it just so happened that the manufacturers
were still stuck back in the "Stink Stack" days, still using selenium
rectifiers.

The problem with the Diode or the NTC solution, is that it does
nothing to save the bulb from line transients.

The NTC worked well because most bulb failures occurred during turn-on.

[snip]

Stepan

On Thu, 04 Sep 2003 14:36:25 -0700, the renowned Lizard Blizzard
wrote:

The NTC worked well because most bulb failures occurred during turn-on.

But soft-starting does not extend bulb life significantly in most
cases. Voltage reduction is what does the trick.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

I think that furthermore, the few volts lost in the NTC aslo goes a
long way to extending bulb life, regardless.

s

On Thu, 04 Sep 2003 22:53:34 GMT, Spehro Pefhany
wrote:

On Thu, 04 Sep 2003 14:36:25 -0700, the renowned Lizard Blizzard
wrote:

The NTC worked well because most bulb failures occurred during turn-on.

But soft-starting does not extend bulb life significantly in most
cases. Voltage reduction is what does the trick.

Best regards,
Spehro Pefhany

I think that furthermore, the few volts lost in the NTC aslo goes a
long way to extending bulb life, regardless.

s

On Thu, 04 Sep 2003 22:53:34 GMT, Spehro Pefhany
wrote:

On Thu, 04 Sep 2003 14:36:25 -0700, the renowned Lizard Blizzard
wrote:

The NTC worked well because most bulb failures occurred during turn-on.

But soft-starting does not extend bulb life significantly in most
cases. Voltage reduction is what does the trick.

Best regards,
Spehro Pefhany