Turntable Speed Using Strobe 33.3

If you can't get a reading that makes any sense with a
fluorescent lamp,it may have a electronic ballast that
is way off of frequency.They are used in a lot of modern
lamps for different reasons.Sometimes to change flicker
rate to cut down fatigue,plus interference problems.The
power companies usually give a fairly steady 60 cycles,
but not voltage.

The frequency of line voltage is almost perfectly controlled: it has to be so as to keep all the generators linked up on the grid in sync. Each day, around midnight, there is a brief time when frequency is adjusted so as to get the number of complete cycles in the day correct. This is done because many timers (clocks) rely on the power frequency for accuracy.

Ordinary fluorescent lights try to minimize flicker, and won't work as well as a simple neon bulb, as in the circuit testers mentioned above.

I'd like to give a "shout out" to everyone who responded and provided vital and important information. This is part of my learning process and I do appreciate. Thanks much all.

Bob