Editing Tractor (section)

=== Levers and switches ===
Many functions once controlled with levers have been replaced with some model of electrical switch with the rise of indirect computer controlling of functions in modern tractors.

Until the late of the 1950s, tractors had a single register of gears, hence one gear stick, often with three to five forward gears and one reverse. Then, group gears were introduced, and another gear stick was added. Later, control of the forward-reverse direction was moved to a special stick attached at the side of the steering wheel, which allowed forward or reverse travel in any gear. Now, with [[Continuously variable transmission|CVT]]s or other gear types, fewer sticks control the transmission, and some are replaced with electrical switches or are totally computer-controlled.

The three-point hitch was controlled with a lever for adjusting the position, or as with the earliest ones, just the function for raising or lowering the hitch. With modern electrical systems, it is often replaced with a potentiometer for the lower bound position and another one for the upper bound, and a switch allowing automatic adjustment of the hitch between these settings.

The external hydraulics also originally had levers, but now are often replaced with some form of electrical switch; the same is true for the [[power take-off]] shaft.