Product Overview
Littelfuse 273.125 MICRO Fuse, One Eighth of an Amp, Five to a Box
Condition
New, unused old stock. The representative pack in the photos is a Littelfuse box with a clear lid: the lid is in place in the first frame, lifted in the edge shot, and off for the overhead frame, so the box was opened for the camera. Inside are five fuses seated in a white molded tray, each with a clear cylindrical body, a dark base, and two parallel pins leaving the same end. The yellow box edge is printed MICRO 1/8 (273). No fuse was taken out of the tray or handled, and no discoloration or damage on the bodies or pins is visible in these frames. We carry this item in depth, so the box that ships is a like unit rather than the exact one photographed.
Same or next business day shipping from our Idaho warehouse. Honest pricing, no nonsense.
Online since 1999. We are here for our customers, with a no-hassle satisfaction guarantee.
Product Overview
The 273.125 is the Littelfuse MICRO series subminiature fuse rated 0.125A, one eighth of an amp, at 125VAC. It is a very fast-acting design meant to open early in an overcurrent event rather than ride it out, which is why it lands on low-current instrument, reference and signal rails where the parts downstream cost far more than the fuse does. The format is the small pin-base MICRO body: a clear tube with two parallel pins exiting one end, so it seats by its pins instead of clipping into a cartridge carrier. The printing on the package edge, MICRO 1/8 (273), matches the 273.125 part number exactly, which is the marking this listing is drafted from. Littelfuse ties the origin of the MICRO line to U.S. space program requirements, and the 273 series has carried that high-reliability reputation since. Against the millimeter rule in the photos the whole five-piece box measures roughly 36 mm across. Interrupting rating, cold resistance, opening time at a stated overload, and operating temperature range are not confirmed here - verify against the Littelfuse 273 series datasheet before use.
Key Features
- Littelfuse 273 series MICRO fuse, part number 273.125
- 0.125A (1/8 amp) rating, confirmed by the MICRO 1/8 (273) printing on the package edge
- 125VAC rating per our catalog data for this part number
- Very fast-acting, quick blow element
- Clear cylindrical body over a dark pin base, as the photos show
- Two parallel pins exiting one end of the body for pin mounting
- Five fuses per pack, seated in a molded tray inside the marked Littelfuse box
- Interrupting rating, resistance and temperature range not confirmed - verify against the datasheet before use
Applications
- Bench technician repairing an instrument that opened its 1/8 amp MICRO fuse and needs the same small pin-mount part rather than a cartridge substitute
- Restorer of legacy aerospace or military electronics keeping the original 273 series protection in place instead of redesigning the holder
- Test fixture builder protecting a low-current reference or signal rail where a slower fuse would let the damage through first
- Maintenance shop stocking a drawer with the exact tiny fuse one stubborn machine keeps consuming
Frequently Asked Questions
What does MICRO 1/8 (273) on the box mean?
It is Littelfuse packaging shorthand: 273 series, 1/8 amp. One eighth of an amp is 0.125A, which is exactly what the 273.125 part number calls out.
How does this fuse mount?
Two parallel pins leave one end of the body, so it seats by its pins rather than clipping into a cartridge holder. The MICRO family was built in more than one lead form, so check your board or holder footprint against the photos before ordering.
Can I tell whether one has opened?
Not from these photos. The tube is clear but the interior reads as solid dark in every frame we shot, so we cannot promise the element is readable by eye - plan on a continuity check rather than a glance. Nothing here has been powered or loaded; these are unused stock.
Will my box look exactly like the one photographed?
The photographed pack is representative of the stock, not the individual box reserved for your order. Series, rating and the printed package edge are what we are selling on; we do not guarantee that every box carries identical secondary markings.
Why buy a five-pack here instead of a bulk box of a hundred?
Because a 1/8 amp MICRO is a part you need in ones and twos. One pack covers the repair and leaves four spares in the drawer, and you can take two or three packs if you are stocking a line that keeps eating them, instead of paying for ninety-five fuses you will never reach. Shipping is a flat $8 per order, free once the order passes $28, and orders leave our Idaho warehouse the same or next business day.
An eighth of an amp is not much current, which is the entire point: the MICRO was built to give up long before anything expensive does. Five of these sit quietly in a drawer for years and then save you an afternoon.
