Bidirectional DC Motor Speed Controllers
Bidirectional DC Motor controllers allow you to switch the direction of the current flow through the motor coils, enabling you to to make the motor turn in either direction, while controlling the speed. Most current DC motor speed controllers change the speed by using a chopper method (Pulse Width Modulation - PWM). Their range is generally from from 0% (full off) to 100% (Full on).
Most bidirectional controllers work by using a H-bridge. Other ways include a DPDT high current switches and relays. All have advantages and disadvantages, though ultimately they all do the same thing in much the same way.
These are used for a variety of different purposes such as Buggies, Go Karts, Golf Caddies, Conveyor systems, Milling machines, Bead rollers, Motorised Fishing reels, kids toy buggies, Quad bikes and so many more applications only limited by your imagination.