Electrical testing devices are tools used to measure, analyze, and diagnose electrical systems and components. Common types include multimeters, which measure voltage, current, and resistance, and oscilloscopes, which visualize electrical signals over time. These devices help ensure that electrical systems operate safely and efficiently. In addition to multimeters and oscilloscopes, other testing devices include circuit testers and insulation resistance testers. Circuit testers check for continuity in electrical circuits, while insulation resistance testers evaluate the integrity of insulation in wires and equipment. Together, these tools are essential for electricians and engineers in maintaining electrical safety and performance.