My variable AC power supply has gone through several revisions over the years. It started out as a simple unenclosed variac (variable autotransformer) and electrical outlet mounted on a block of wood. I eventually put it in the case of what used to be an old audio signal generator for safety and appearance. Among the other added features, I used a 0-250VAC analog meter that I had on hand to display the output voltage because otherwise it was annoying to whip out the multimeter to monitor the voltage coming out of the variac. Over the years I realized that the meter was inaccurate and simply useless, so a new readout was necessary.
Digital AC Voltmeter - [Link]