If you’ve never used a voltmeter to test electrical circuits on 12-volt farm equipment, cars or trucks, but wanted to learn, here’s how: Voltmeters cost from $15 to $300. $50 will buy an economy-grade ...

[Martin Lorton] has a vintage Harmon 4200B selective voltmeter that needed repair. He picked it up on eBay, and he knew it wasn’t working, but it was in good condition, especially for the price. He’s ...

A customer recently called to ask questions about the electrical system on his machine. I asked if he had a voltmeter. There was a long pause, then he said, “Yes, but I don’t know how to use it.” He ...