Yeah that's it way of temp regulating.
Ensure you have a couple of spare bulbs handy close by and that you change them over BEFORE they fizz and die on their own. I say this as I know someone who used one of these and the bulb died sometime overnight and eggs went stone cold. Although she put a new bulb in next morning on waking its hard to know if it affected the eggs after that. Only 2 went on and hatched. Others seemed to not to have progressed.
Also please know these incubators don't give the greatest results. They are the cheaper end of the scale and can really crap out and give very mixed/poor hatch results. Depending on where you have it standing, the outside temp, humidty around it etc can all lead to hit and miss results. Also during hatching you really need to ensure you don't lift that lid and you hovver round to ensure humidty is as good as it can be.