RN55 75 Ohm Precision Film Resistor, 1/8 W, MIL-R-10509/7
- 3 photos
Never used. The original pack has been opened, or the quantity was split off a full reel or tube. Leads are original and unclipped.
New old stock, open stock on the grading scaleSend the quantity you need. You get a quote back with shipping before anything is charged.
Video
Filmed on the bench. Sound is stripped from product clips.
- 0:05
Specifications
| Specification | Value |
|---|---|
| Identification | |
| Part number | RN55 |
| Manufacturer | Not recorded |
| Condition | New old stock, open stock |
| Date code | Not recorded |
| Package | Axial leaded, through hole |
| Country of origin | Not recorded |
| Family | RN55 |
| Stock number | NFK65RKW |
| Overview | |
| Style | RN55, to MIL-R-10509/7 |
| Manufacturer | Unmarked. See the description |
| Electrical | |
| Marked value | 75R0, that is 75 ohms |
| Power rating | 1/8 W, 0.125 W |
| Tolerance | Not legible on these parts and therefore not claimed |
| Construction | |
| Construction | High stability metal film |
| Package | Axial leaded, through hole. Light blue body |
| Condition | |
| On the shelf | Fifteen, sold individually |
| Condition | Vintage old stock. Never installed, never soldered |
About this part
RN55 is not a value, it is a style. The designation comes from MIL-R-10509, the United States military specification for high stability metal film resistors, and it describes the construction, the size and the qualification rather than the resistance. A part built to it is made to hold its value across temperature and time far better than a general purpose resistor, which is why these turn up in measurement circuits, reference dividers and anywhere a gain is set by a ratio that has to stay put.
This one is marked 75R0, which is 75 ohms in the notation that puts the multiplier where a decimal point would go and cannot be lost to a bad photocopy. The RN55 body size is rated an eighth of a watt. The light blue body is characteristic of the type.
One thing this listing will not tell you is the tolerance. The suffix letters that encode tolerance and temperature coefficient are not legible on these, and no inventory paperwork came with them to say otherwise. RN55 parts are commonly one percent, and commonly is not a specification, so it is not claimed here. If your circuit depends on the tolerance, measure one before committing.
Fifteen are on the shelf and they are sold individually. Expect lead oxidation from storage. None has been fitted.
Questions about this part
What does RN55 mean?
It is a style, not a value. The designation comes from MIL-R-10509, the military specification for high stability metal film resistors, and it describes construction, body size and qualification. The resistance is separate, and on this one it is marked 75R0.
Why does the marking read 75R0 instead of 75 ohms?
The R sits where a decimal point would go, so 75R0 is 75.0 ohms. It is done that way because a decimal point is the first thing lost to a bad print, a scratch or a photocopy, and a misplaced one is a factor of ten.
Are these one percent?
We do not know and will not claim it. The suffix letters that encode tolerance and temperature coefficient are not legible on these, and no paperwork came with them. RN55 parts commonly are one percent, and commonly is not a specification. If your circuit depends on it, measure one first.
What is a high stability resistor actually for?
Anywhere the value has to stay where you put it: measurement circuits, reference dividers, gain setting pairs where the ratio matters more than the absolute value. A general purpose resistor drifts with temperature and age enough to matter in those places, and this construction is what was specified instead.