The "flicker " in AC bulbs is extremely difficult to detect visually since the difference between maximum and minimum is only a few percent. As for fluorescents, if they use a magnetic ballast then you have flicker (0-100% difference) at twice the mains frequency (100Hz in Europe, 120Hz in US). If its a newer fluorescent then it should have an electronic ballast and the flicker frequency is going to be 20-40kHz. Good luck trying to see that. As for LEDs, the frequency can vary. Most decent LED lamps will use a switching power supply which pushes the major artifacts into few hundred to few thousand Hz range. The filament style bulbs are the worst and will be as bad as magnetic ballasted fluorescents. Even a small capacitor though can improve the perception. Go for a cheap LED bulb/fixture and you will get exactly what you pay for.