Re: recirculating fan questions
A fan at full speed can be a bit loud, audible anyways, and might disrupt something very quiet, like some frog calls. Turning the speed down a bit turns the volume way down though, and provides a gentler breeze, which is what I think you want. You can do that by placing around a 50ohm resistor in line with each fan, which is also accomplishable with two 100ohm resistors in parallel, and they're super cheap. Or you could just use a 9v power supply, I'd test it with a 9v battery first to see if you're getting the kind of airflow you want.