RN55D7501FDale Electronics
$55.001000 in stockAsk for a quote
Manufacturer
Dale Electronics
- Condition: New old stock, sealed
Dale Electronics was a Nebraska resistor company, headquartered in Columbus with plants across Nebraska and South Dakota, and it built its reputation on precision and on military qualification rather than on price. It was acquired by Vishay Intertechnology in 1985 and the line is sold today as Vishay Dale, so a resistor bought here as old stock usually has a datasheet that is still in print. Parts carrying either marking are listed on this page.
What they were known for. Precision wirewound resistors first, then precision metal film, then the military styles that made the name. Dale was one of the principal suppliers of RN and RNC series resistors built to MIL-R-10509 and its successors, the small axial parts that a defence or instrument schematic calls out by military style rather than by value. It also made resistor networks, current sensing elements, and a large range of inductors and magnetics.
Why an RN part is different. A military style is a specification of the whole part, not just its tolerance. RN55 fixes the body dimensions, the lead diameter, the power rating, the temperature coefficient class and the qualification testing the lot had to pass. Two resistors can both be 1 percent and behave differently across temperature and time, and when a schematic asks for RN55D it is usually asking for the stability rather than for the accuracy at room temperature. The RN55D7501F on this page decodes as the RN55 style, temperature coefficient class D, 7.5 kilohms, 1 percent, and the 9903 date code puts it in the third week of 1999.
What this means for old stock. Metal film resistors are the least troublesome thing in this catalog. Nothing in one is chemically active at room temperature, the film is sealed under a conformal coating, and a part built to a military qualification was screened harder than a commercial one to begin with. A sealed Dale lot from the 1990s is, for every practical purpose, a lot of new resistors, and the date code on it is provenance rather than a warning.
Questions about Dale Electronics
How do I decode RN55D7501F?
RN55 is the military style and case size, roughly a quarter watt in a small axial body. D is the temperature coefficient class. 7501 is the value in three significant figures plus a multiplier, so 750 followed by one zero, which is 7.5 kilohms. F is 1 percent tolerance. The scheme is defined by the military specification rather than by Dale, so it decodes the same way whoever made the part.
Is Vishay Dale the same as Dale Electronics?
The same operation under later ownership. Dale Electronics was an independent Nebraska company until Vishay Intertechnology acquired it in 1985, and the Dale name stayed on the product line rather than being absorbed. Many part numbers ran straight through the change, so a datasheet for a current part will usually describe an old one correctly, and stock marked either way is listed together here.
Does a 1999 date code mean the resistor is worn out?
No. A date code is a manufacturing fact, not an expiry. Metal film resistors have no aging mechanism at room temperature and a sealed lot has not been exposed to anything. We record the code because it is provenance and because it tells you which production the lot came from, not because it says anything about condition.
Can I substitute a commercial 1 percent resistor for an RN55?
Sometimes, and you need to know what you are giving up. You will usually match the tolerance easily and may not match the temperature coefficient class, the power rating in that body size, or the screening. In an instrument reference or a bridge, the coefficient is the thing that matters and the substitution can be the fault. In a divider that feeds a digital input, nobody will ever know.
Do you sell these in small quantities?
The sealed lots are priced and sold as lots, because opening one ends the seal that makes it a known quantity. Ask for the count you want and we will check whether there is an open stock lot of the same part number, and if there is not we will tell you what splitting the sealed lot does to the grade and the price.