RV lamp extender
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.
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