Details

The Power DAC Shield is a digital-to-analog converter shield for Arduino boards. It has 12 bit resolution and can generate true AC waveforms when using a bipolar power supply (positive and negative voltage).

The "Power" in the name comes from the fact that the shield can be used to drive up to 250mA at +-15V (3.75W). That's enough to drive small DC motors and home audio speakers! A resettable PTC fuse protects the output in case things get carried away ^_~

While the Arduino's analog outputs generate PWM signals, the Power DAC Shield provides a true analog voltage. That means that you can use it in many applications, such as motor drives and audio, where PWM would not work.

The Power DAC Shield uses SPI to communicate with the Arduino, allowing up to 4 to be stacked while leaving most of the Arduino's IO free for use by other shields or for connecting to other parts of your project.

Details
DAC IC: MCP4921
Input V+
Max: 15V
Min: 5V
Input V-
Max: -15V
Min: -5V
Output Vpp
Max: 30V
Min: 0V
Output current protection
Trip - 0.250 A
Hold - 0.100 A
Output frequency
220kHz
Logic is compatible with 5V Arduino boards like the Uno and Mega. The shield will not work with 3.3V boards like the Arduino Due.
Output voltage is sourced from an external supply (see connection diagram and V+ and V- specs above)

Use Cases
Audio output
Driving small DC motors
Driving big DC motors with an external power amp
Drawing Lissajous figures and other shapes on oscilloscopes
Anything requiring precise, true analog voltage output