Correct option is A
An
idler gear is used in gear trains to transmit motion and achieve the desired direction of rotation of the driven gear without altering the gear ratio. It is positioned between the driving and driven gears. While idler gears do not affect the speed or torque ratio, they reverse the rotation direction or bridge distances between gears.
They do not affect the gear ratio because the number of teeth does not matter for intermediate gears. The gear train's speed ratio is determined solely by the driving and driven gears.
Applications:
· Used in gearboxes, conveyors, and machinery where reversing rotation or spanning distances is needed.
· Common in complex systems like automotive transmissions.
