Can I just slap a voltage regulator in-line, or do I need to engineer a circuit design? I am building a motor drive for a mechanical speedometer. A 2000 pulse per mile signal is produced in the transmission. I am using an arduino to translate that signal to a PWM to drive a motor connected to the back of a mechanical speedometer. It works on the test bench and now I am ready to connect it to a vehicle. The Arduino runs on 5 volts and can take up to 12 volts. During development of the code, I used a bench function generator for the 2000ppm frequencies set at 5 volt. In the vehicle, the 2000ppm signal is 12 volts, so I have added a 5 volt regulator. With the function generator set to 12 volts, the 5 volt regulator does it’s job. I’m ready to connect to a vehicle for a final test. I notice my truck produces 14 volts with the engine running. I’m thinking I can add a 12 volt regulator for both the motor and the Arduino. This seems like a simple fix, maybe too simple? I usually get away with connecting electronic components to create circuits, and they work. I skip the math part of engineering, but am still interested in learning that part. I am an electronics tech of 30 years, maybe I’ll be an engineer someday. I know this is not audio related, but I’m not sure where to ask questions about this. I am a member of an automotive site, but this is more of an electronics subject. If I had a 12 volt regulator in hand, I would implement it and see the results, but I don’t so I thought I’d ask here for feedback. I have worked on power supplies that do have adjustable voltage regulators and resistors, diodes. I’m shooting for a dedicated 12 volt reg.