A Great introduction to the Field of Electronics! Build over 60 electronic projects including a finger touch lamp, a metal detector, a transistor radio, and an alarm with the 60-In-One Electronic Playground. Learn about voltage, currents, resistors, capacitors, and much more. Uses spring hook-up method. The Electronic Playground & Learning Center is easy to understand and comes fully assembled with all electronic parts and step-by-step instructions. It requires one 9-volt battery (not included).