Motor shield

L293D use 16 pin DIP package, its internal integration is bipolar H - bridge circuit.
This kind of bipolar pulse width method has many advantages, such as the current continuous, or micro current vibration when motor stops, which as a lubrication effect. It can eliminate the dead zone of static friction when positive and negative.
2 interface for 5V servomotor connected to the dedicated high-resolution timer - no vibrations.
The extension card can power 4 CC engines or 2 step-by-step engines or 2 servomotors.
Up to 4 two-way CC engines with 8-bit individual speed selection; up to 2 step-by-step motors (unipolar or bipolar) with single coil, double coil or not intertwined; 4 H bridges: per bridge provides 0.6 A (peak current 1.2 A) with thermal protection.
The pull resistance keeps the engines off while powering up; built-in reset button.
2 external power stations, for separate logic/engine blocks. Fully compatible with Mega, Diecimila and Duemilanove