There's a thread over on /strek/ about that franchise's weapons
>>>/strek/14060
Trek is an example of how not to do it from a writing perspective. They had no idea how much power to give the things.
A TNG-era phaser on maximum setting is capable of vaporizing 650m^3 of rock in a 1s burst, according to reference books. This is backed up by dialogue (e.g. Riker threatening to destroy a hospital). However, when it comes time to actually use the thing, anything you can fit behind is viable cover. These things are handheld WMDs, but in every fight scene they're apparently left on setting 2-3 of 16. There's a huge disagreement between what we're told and expect phasers can do, and what we see them do.
The disconnect can be amusing at times, such as when O'Brien plans to kill himself - and turns the phaser to maximum, meaning he'll take an entire section of the ship with him.