I have a herpstat 2 that has a program built in to gradually raise the basking light power via built in dimmer over a set period of time. As for UVB, you can't dim them the same way but I set it to turn on later after the basking light has been on for a bit. My thinking is that this imitates a sunrise/sunset and the high UVB levels happen in mid morning to late afternoon like they would in the wild.