Air Conditioning - Cycletime of Air Handler blower

What determines when the air handler blower turns off? My compressor(outside unit) will kick off, but my air handler blower will continue to run for quite awhile afterwards. I think somebody had said it may be the timer relay. Where would i find this timer relay, or could it be the thermostat, or is there a certain electronic board that has the timer circuit built into it? Thanks in advance.

different manufacturers will handle the blower post run times differently. Typically there will be an Time delay Relay that controls the blower some are adjustable some are not. Is it staying on so long after the compressor shutdown that it annoys you or what?

Basically yes, it annoys me that it's not running the way it should. If it ran the same way all the time it probably wouldn't bother me. I may be totally wrong, but when it runs for 15-20 minutes after the compressor is off, and the duct work is all in attic, isn't it just warming up my house. Sometimes the air handler kicks off about a minute after reaching setpoint and the compressor kicks off.

Will the air handler running that much affect my electric bill? Should it be something i don't need to worry about?