On Thu, 22 Mar 2007 09:11:44 -0700, "RST Engineering"
wrote:
wrote in message
...
[ too-bright VOR/ILS indicators]
I wonder if it would be possible to install lower-wattage lamps in the
VOR/ILS indicators, or install a (fixed) resistor or diode in series
with the existing lamps in the indicators.

Or you could do it the right way and design a switching regulator with
filtering for noise so that one output goes from x to y with control
rotation, another from w to z, and still a third (inverse) output
from v to u.

Well, _you_ could do it the right way over the weekend. _I_ could do it
the right way after a couple of trips to Frank's Transistor Barn for
another 1-lb bag of MOSFETs to replace the ones I would blow up. In
the general case, IMHO, installing a lower-powered lamp is something any
repair station should be able to do, and installing an inline resistor or
diode is something that most repair stations could probably do. Also,
I know you mentioned filtering, but "switching power supply" and "AM
radio" makes me a little nervous.

The reason you don't start at 0 and go to + supply is that most lamps
will last thousands of hours if they are prewarmed before running them
up to ratings.

I know some dimmers for stage use do this, but there, I think the
"warming" current that flows even with the knob on 0 is there to get the
lamp to respond faster when you suddenly turn up the knob. On AC, lamps
also last longer if switched at the zero crossings of the waveform.

Matt Roberds