Product Overview
5-Pack Littelfuse 273.125 MICRO TR3 Fuse 0.125A 125VAC – Unused, New Old Stock
The Littelfuse 273.125 MICRO TR3 fuse delivers very fast-acting protection for precision electronics and compact control systems. Originally developed to meet stringent U.S. Space Program requirements, this fuse continues to define reliability in miniature circuit protection.
Product Condition
Unused, New Old Stock (NOS). Stored in original Littelfuse packaging, with leads and housings in excellent condition. Clean and ready for installation in compatible MICRO fuse holders.
Product Overview
The Littelfuse 273 series exemplifies micro-sized engineering built for speed and accuracy. With a 0.125A rating and 125VAC capability, the 273.125 fuse responds instantly to overcurrent faults—protecting sensitive components from irreversible damage. Known for its aerospace heritage, this design remains a benchmark for precision and high-reliability performance.
Key Features
- Rated current: 0.125A (1/8 amp) at 125VAC
- Very fast-acting (quick blow) response time
- High breaking capacity: up to 10,000A
- Compact MICRO TR3 format for dense PCB layouts
- Available with plug-in or radial leads
- Typical opening: <5 seconds at 200% current
- Low resistance (approx. 1 ohm)
- Operating range: -55°C to +85°C
- Visual inspection option with clear cover
- Trusted Littelfuse quality, used in mission-critical electronics
Applications
- Precision electronic assemblies
- Military and aerospace equipment
- Industrial control systems
- Measurement and instrumentation
- Power regulation and feedback circuits
- Compact high-reliability power modules
- Prototyping of fast-acting protection systems
Frequently Asked Questions
What makes the MICRO TR3 series unique?
It was originally designed for aerospace programs requiring high precision, compact size, and extremely fast response to current faults.
Is this fuse suitable for both AC and DC circuits?
Yes, it supports protection across 125VAC and equivalent DC voltage environments within its rated parameters.
Can it be visually inspected?
Yes—select models include a clear cover for quick verification of fuse element integrity.
How does it perform under overload?
At 200% of rated current, the fuse opens in less than five seconds, ensuring minimal damage to downstream components.
Why is this model valued by engineers?
Its fast-acting precision and space-efficient design make it ideal for high-stakes, high-density circuit protection.
From its roots in aerospace to today’s precision circuits, this Littelfuse MICRO fuse carries a legacy of engineered reliability—ready to safeguard your next design.
