Building an electrical circuit is tough, and can even be frustrating when that circuit is not complete or does not work as it should. When this happens, using a voltmeter can help to diagnose the problem. This device detects current in the form of voltage along an electrical circuit. You might come across several different types when working on electronics. The most common is the analog voltmeter. It is portable and often takes batteries. You can read both AC and DC current with the indicator line. Another type is the digital voltmeter, used in professional applications. Its error rate is less than one percent, making it the most accurate type you can purchase. Both types of voltmeter are available from reliable sellers on eBay. Choose which type you need based on its application. For everyday use, the analog type is inexpensive and relatively accurate. However, in a lab setting or when building electronics for an occupation, choosing a digital version is more appropriate.