Engineering

Mechanical calculator: carrying a number

Turn a stepped-drum calculator and watch decimal wheels add or subtract, including carry and borrow between columns.

Actual application image

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Choose an input number and turn the crank. Set the cycle frequency to zero for manual turns. Try subtracting through zero.

Exact four-digit arithmetic modulo 10000 with an illustrative stepped-drum mechanism. Gear forces and historical machine tolerances are not modelled.

Equations used in the module

Equations
result_new = (result + sign operand) mod 10000

Engineering

Fill and drain a lock chamber, equalise the water levels and open the interlocked gates to move a boat between reaches.

Engineering

Adjust the sheet and rudder while apparent wind, sail pressure and the keel combine to move a sailboat.

Engineering

Compare passenger loads and watch the shared cable, traction motor and regenerative braking move two cars along an incline.