The R452.750MR is a Radial Lead PTC Resettable Fuse from Littelfuse Inc. PTC resettable fuses, also known as polymeric positive temperature coefficient devices, are overcurrent protection devices used in a wide array of electronic applications. These devices protect against damage caused by excessive current flow, automatically limiting current and resetting when the fault condition is removed.

Applications:

• Overcurrent protection in power supplies
• USB port protection
• Speaker protection
• General electronic equipment protection
• Telecom equipment

Features:

• Resettable overcurrent protection: Eliminates the need for manual fuse replacement.
• Radial leaded package: Facilitates easy mounting on printed circuit boards.
• Fast trip time: Quickly responds to overcurrent conditions, minimizing damage.
• Low resistance: Minimizes voltage drop during normal operation.
• Compact size: Saves space on circuit boards.

Benefits:

• Enhanced circuit protection: Protects sensitive components from overcurrent damage.
• Reduced downtime: Automatically resets after a fault is cleared, minimizing equipment downtime.
• Lower maintenance costs: Eliminates the need for fuse replacement, reducing maintenance efforts and costs.
• Improved product reliability: Prevents damage from overcurrent events, increasing the reliability and lifespan of the protected equipment.
• Safe operation: Limits current flow during fault conditions, preventing potential hazards.

Additional Details:

The R452.750MR has a hold current of 0.75A, which means it will carry up to 0.75 Amps continuously at the rated voltage and temperature without tripping. The trip current will be higher, and depends on voltage and ambient temperature. The 'MR' suffix typically indicates a specific packaging or manufacturing variation. Consult the Littelfuse datasheet for precise specifications on trip current, voltage ratings, operating temperature range, and agency approvals (e.g., UL, CSA, TUV). The component is constructed using a polymeric material containing conductive particles. When current exceeds the trip current, the device heats up rapidly, causing a significant increase in resistance, thereby limiting the current. When the overcurrent condition is removed and power is cycled or removed, the device cools down and returns to its low resistance state, restoring normal circuit operation.