What is needed to take a 0-5Vdc output from a DAC and amplify it to 0-30Vdc to drive an analogous solenoid valve? The signal must be linear: 1V = 6V, 2V = 12V, etc., so simple transistors seem to be out of the question.
I'm powering a 12V 0.16A fan with a 9V battery. Will it drain the battery at more, less, or exactly 0.16A?