How can I control an analog voltmeter's gauge using a dimmer switch?

I am trying to build a device that controls a voltmeter’s gauge. The end result would be a dimmer switch that is able to control the gauge bringing it back and forth with ease. Right now, I have the dimmer switch wired to a computer brick (transformer & rectifier) and that runs into a light fixture. The output of the computer brick is 15v 4a. The idea is to have the voltmeter parallel to the light fixture. I just purchased a dc light bulb from a marine store but it doesn’t seem to be working because the amperage is off. Do I need to find something that is exactly 15v 4A or would a 12v 6A or a 12v 2A bulb work as well? Any suggestions on something I could use if a light bulb doesn’t work? Also, is my electrical circuit sound? Will this work?

outlet > dimmer—> computer brick—> light fixture <> voltmeter (in parallel)