Here is 1 - 5 amp capable H-bridge DC motor driver. This keeps the final circuit in the “cheap” category which was one of the design parameters we’re optimizing for.The fast recovery diodes (shown in light blue) are optional when you are using the TIP102/107 as those transistors have a diode built into them. However you can include them for greater protection at higher currents and still keep the cost at $5 per bridge.source

This is Small DC Motor Speed Regulator It keeps permanent magnet motor running at constant speed regardless of load .Reverse engineered circuit diagram of a motor speed regulator out of a portable pocket tape recorder containing a single motor for all functions. This circuit works amazingly well, keeping the motor speed constant regardless of shaft load and battery voltage. source

This is an actual reverse engineered circuit diagram of the one transistor circuit most commonly used to drive Permanent Magnet DC motors in childrens’ toys. This type of circuit almost always uses the 625mW version of the ubiquitous 8050 or 8550 transistor. It is vital to note that there are two different varieties of each of these two transistors, and although they are often stamped with the same part number, they are not interchangeable because one is a 625mW part with a higher VCEsat, while the other is a 1W part with a lower VCEsat.source

This Stepper Motor controller controlled by PIC16F84.In the PM type stepper motor, a permanent magnet is used for rotor and coils are put on stator. The stepper motor model which has 4-poles.In case of this motor, step angle of the rotor is 90 degrees.source

Two small pushbutton switches, a few diodes and two relays form a method to control on/off power to a brush motor as well as the motor direction. The circuit was originally designed for a motorized lifting platform.source