I'm trying to run a linear actuator. It's 12 volts and 150 milliamps so I'm using a power supply for it. However, the PWM signal has to come from the Arduino. What's happening when I hook it up is that I'm getting an open circuit instead of a PWM signal (if I replace the actuator with a resistor to ground I get the proper signal). I'm using a Mega so I can sink 200 mA into a ground. Would hooking the ground into the Arduino instead of the power supply fix my problem? Would that mess with the power supply voltage by having a different ground?
Here's the datasheet on the linear actuator. https://secure.robotshop.com/content/PDF/L12_datasheet-RB-Fir-38.pdf It's the 210:1 gearing at 12 volts.