I have a 1995 Honda Civic EX with the 1.6 liter VTEC engine. It seems to run well, except for an occasional rough idle. I have noticed that when I turn the headlights on, the clock on the dashboard gets dimmer. I have also noticed that after the engine is warmed up, if I turn the headlights off while the car is idling, the idle speeds up. Do these things point to a bad voltage regulator? If not, what causes these things? Do I need to do anything?

All normal.