Extending the life of RV lamp bulbs

[k7elp60]

I have developed a circuit that extends the life of lamp bulbs like the 1141, 912, and the 913 that are used in RV lamp fixtures. What the circuit does is it eliminates the surge current when the lamp is first turned on.
In addition to a travel trailer that I have installed this modification to the lamp fixtures I have some RV lamp fixtures mounted to the headboard of my bed, and use the lamps for reading. These original bulbs have over 6 years of use without failure.
The cost of parts to build this circuit is about $2.00.
My question to the readers of this forum is. Do you think this is a circuit you would be interested in building a using in your RV?
73
Ned
K7ELP

[Radio]

Sure, post it for us. A schematic or other graphic can be attached to a thread (scroll down on the thread editor page) or you can upload files to the "download" section in the menu box on the left of the home page.

And welcome to ORR.net

Radio

[k7elp60]

Originally Posted by Radio

Sure, post it for us. A schematic or other graphic can be attached to a thread (scroll down on the thread editor page) or you can upload files to the "download" section in the menu box on the left of the home page.

And welcome to ORR.net

Radio

I'll get the schematic ready and post it.
Ned

[aintgotnun]

sounds pretty neat to me

Welcome to ORR!!

[AE5BI]

I am going to LED replacements. I have some coming in the mail this week. I figure the mechanical wear on the filaments when travelling can't be god for them either. I went through 3 (different) bulbs in about a month.

[jagco]

I'd be interested, too. Post away....

[k7elp60]

Here are the schematics. I say schematics as when I first posted to this forum I was working on a second version. The schematic that has the IRFZ44 n channel mosfet is the first version. It has had several revisions in the process. To make a long story short it works the best and the drop across the mosfet when the lamp is on is only about 20mV.

The schematic with the IRF9530 p channel mosfet is the latest one. Since the Rds of this mosfet is higher the voltage drop when the lamp is on is 0.25 volts.

Both schematics show a bulb #1141, but I am sure both circuits will work with the 912's and the 913's.
The last figure shows the extender installed in a Bargman lamp fixture. In this picture a negative temperature coefficient thermistor (round disc) instead of the 5.6 ohm resistor, and different values of resistor and capacitor, as well as the IRFZ40 mosfet. This was the original design.

[w6pea]

Looks great to me.
Happy New Year.
73 de w6pea