Round to Square Pigtail Connector

A pigtail round-to-square connector is an adapter cable that converts an older 7.9mm round DC jack to a newer square DC input for Lenovo and IBM ThinkPad laptops.OverviewA round-to-square adapter pigtail allows you to use an older power supply with laptops that have transitioned from a round 7.9 x 5.5mm DC input to a square-shaped DC port. These adapters are commonly used with Lenovo ThinkPad Edge, X1 Carbon, Yoga, and other models that require a square DC input while maintaining compatibility with older round-jack chargers .Key FeaturesConnector Type: Converts 7.9mm round female jack to square male plug with pin .Compatibility: Works with IBM and Lenovo ThinkPad laptops; ensures proper recognition of the power supply via an internal IC chip .Power Handling: Supports the same voltage and current as the original AC adapter; some models identify as 90W with a 550-ohm signal-ground resistance .Design: Compact, durable, and easy to manage; typically a two-core cable with thick insulation for long-term use .Additional Functionality: Some adapters also provide a USB charging interface (5V 1A) for mobile devices .Usage ConsiderationsEnsure the AC adapter voltage and current match your laptop's requirements to avoid damage .Some laptops may prompt a warning if the adapter is not recognized, requiring a manual confirmation (e.g., pressing Esc on startup), .The adapter is primarily for power conversion, not for data transfer.Where to BuyThese adapters are available from multiple online retailers, including Amazon, eBay, AliExpress, and Walmart . When purchasing, check the product description to confirm compatibility with your specific ThinkPad model and ensure it includes the IC chip for proper power recognition. This adapter is a practical solution for extending the life of older Lenovo power supplies while maintaining compatibility with newer laptop models.