I'd love it if there was a circuit connection that would simply send a signal if it was operating (shining on an enemy).

this would greatly simplify power saving laser turret designs by allowing someone to connect a wall section of laser turrets to a power plug and only enable those laser turrets when the spotlight (with its greater range) has targeted an enemy.

ex spotlight outputs A when shining on enemy and plug is enabled when it receives A, laser turrets are on a grid "past" plug meaning the passive drain of the laser turrets is equivalent to the passive drain of the single spotlight. Unless the enemies are approaching from behind, where the spotlight can't see.

This is already implemented (sans circuit connection, as the prototype for electric turrets is hard coded).

energy_source =
{
type = "electric",
buffer_capacity = "15kJ",
input_flow_limit = "15kW",
drain = "0kW",
usage_priority = "secondary-input"
},

A buffer of 15KJ is stored (the cost of one cycle), with no drain for being connected. Searchlights only use power when they are active. I hope this clarifies things.