Hi all.Maybe a stupid question, but anyway: Building a 737-sim, I was wondering why there is 2 ways to apply elevator trim? I

I believe on some planes the yoke switches are electric trim tied to the autopilot, with the manual wheel as a backup. I believe whole point of the yoke switch is so that you can keep a hand on the yoke and another on the throttle, without having to move one to trim.On that note - does anyone know of a hardware trim wheel that's affordable?

Thank

As david saya. Just to add that the ability to manually revert to controlling pitch with no electrics or fly by wire computers functioning is part of the Certificate of Airworthyness is most countries. Therefore the trim control in the A320 is still, I believe, hydro-mechanical but the elevator is controlled through the FBW system.