We had company staying with us most of the week, so that pretty much killed any time I had to work on the aircraft. Terry left today for a week on the road, so I wanted to spend time with her on Saturday.

What little building time I got in before today was spent on running a few more wires for the electric pitch trim. I spent way too much time trying to find a good routing for a couple of those wires.

I also started thinking about the four annunciator lights I will have. I hadn't considered it before, but I realized that I should come up with a way to dim those lights for the times that I fly at night. Each of the lights is controlled by power that is switched to put the light ON or OFF. I couldn't come up with a simple way to dim these lights, so I posed the question to the Aeroelectric-List. Bob Nuckolls suggested using a zener diode that would be switched into the common ground of the lights. This would reduce the voltage drop across the lights, but it would only give a single fixed level of dimming. I would also have to experiment to find the optimum value of the zener diode.

A helpful guy from Finland suggested another solution, using a PNP transistor as a "transistorized negative voltage emitter follower" (his words, not mine). This way I could use a potentiometer to control the intensity of annunciator lights. We exchanged several e-mails to discuss details of the circuit, and eventually he came up with an interesting option to use a SPDT switch ON-OFF-ON switch to give three operating modes: Full bright, Dim (intensity controlled by the potentiometer) and Auto (full bright if the position lights are OFF, and dim if the position lights are ON). I picked up the components a couple of days ago, now I need to assemble the prototype to try it out. If this works, I'll post the circuit diagram once I've sorted it out.