A voltage tester is a simple electrical tool used to check the presence of voltage in a circuit. It helps ensure safety by indicating whether wires or electrical devices are live. Voltage testers come in various types, including non-contact testers and multimeters, each designed for specific applications. Using a voltage tester is straightforward. You place the tester's probes on the circuit or device you want to check. If voltage is present, the tester will light up or beep, alerting you to the electrical current. This tool is essential for electricians and DIY enthusiasts working with electrical systems.