Riedon Company Blog

Resistor Technologies: Wirewoud, Foil, Thin Film & Thick Film

Riedon provides resistors which encompass all four of the basic resistor technologies.  As you can see these are wirewound, foil, thin film and thick film.  Each technology has it’s own advantages. As you have inquiries be aware that we have this breadth of capabilities.  Please call us to discuss your specific application. 

Resistor Technologies


Resistors’ Lead Time & Crosses to Vishay, Ohmite, Caddock, IRC

Riedon & lead timeWhile our competitors’ lead times have increased, Riedon still offers the best delivery and the finest customer service in the industry.

  • Delivery in an average of 4-5 weeks
  • Premium delivery time of 1-2 weeks!
  • Custom solutions are available even for the most unique applications
  • Riedon is now an ISO 9001 company

Riedon offers crosses to 37 various resistor manufacturers , we can review your resistors specs and offer crosses or new solutions. Put us in touch with your Engineers and our expert team can help!

For Vishay cross list; click here

For Ohmite cross list; click here

For Caddock cross list; click here

For IRC cross list; click here


Resistors : Medical Application

MedicalresistorsMedical electronics equipment is not longer just found in hospitals, clinics and doctors surgeries. Neither is its use restricted to qualified practitioners. Instead designs have become smaller, more portable and easier to use to the point where now appliances like defibrillators are deployed in many public places such as sports venues, schools, airports, health & fitness clubs and many commercial and government offices. Other devices such as blood glucose meters are today considered essential in the care of patients with diabetes and have evolved to be personal, pocket-sized units that can be carried everywhere. Then there is equipment for patient monitoring, diagnostics and medication delivery that has been designed for in-home use, which often includes portable, body-worn elements. Medical equipment generally demands the highest quality components to ensure safe and dependable operation; and portable equipment poses the additional challenges of compact size, the ruggedness needed to cope with harsh operating conditions, and usually needing to be battery-powered. This article will explore two of these applications for portable medical electronics, looking at the specific requirements of the resistor technology used in their circuit designs. It will then examine potential solutions based on products from Riedon, a specialist resistor manufacturer and supplier.

Continue to read here 


Temperature Coefficient of a Resistor; What it means?

In wirewound resistors, another selection factor is the temperature characteristic of the wire.

The resistance of all materials changes as their temperature changes. If the temperature is lowered, resistance (typically) declines. In fact, if cooled sufficiently, the material becomes a "superconductor" with no significant resistance. Increasing the temperature (typically) increases resistance. The temperature coefficient of resistance (TCR) of wire or a resistor relates the change in resistance to the change in temperature. It is usually expressed as "parts per million per degree Centigrade" (TCR = ppm/C.) The temperature coefficient of resistance, then, tells you how much the resistance changes (ppm) if the temperature changes one degree Centigrade.

Sometimes, we measure temperature in degrees Fahrenheit. But today, degrees Centigrade is more common and acceptable. Special wire alloys are formulated to have special temperature coefficients. For example, "Evenohm" (a trade name for a low TCR wire alloy) is formulated to have a small TCR of 5 to 10 ppm/C. Pure nickel has a much larger TCR of 6700 ppm/C. Copper has a TCR of 3900 ppm/C. These, and other alloys allow us to "tailor" the resistor to desired characteristics in applications where temperatures change. As a practical example, a resistor with a resistance of 1000 ohms, made from pure nickel wire, would have a new resistance of 1670 ohms if we increase its temperature from 20C to 120C. In the same application, a resistor made with Evenohm wire would increase to only 1001 ohms.


A second life for ammeter shunt resistors

Click here to see our latest published article about our newly released ammeter shunts :

The growth in energy supply from renewable sources: solar, wind, and wave or tidal power, is also prompting an increased demand for more accurate high-current measurement solutions. This isn’t simply to enable utility companies to better measure the power contributed to the grid for billing purposes, or to achieve more precise control of the generating plant. Rather the need for improved accuracy over more conventional electricity metering devices is to ensure the warranted performance of the various elements of a distributed power system. A return to the principles of traditional ammeters that employ shunt resistors for high-current handling appears to be the answer.

Continue to read here: ECN

DC Ammeter shunt

DC Ammeter Shunt Resistors


Wirewound Resistors vs. Film Resistors

Wirewound resistors have been around for a long time. They enjoy a long life because they have some very important features not duplicated by new technology products. If you must optimize circuit designs where precision is important, you should understand those characteristics.

fundemental construction of wirewound resistorsFor most of the history of electronic and electrical circuits, wirewound resistors were the only game in town for precision resistances. Wirewound precision resistors have some important characteristics. First, they can have very tight resistance tolerances . . . 0.005% is commonly achieved. More important, they are stable (15-50ppm/yr) maintaining their precision over time because they are made with stable materials. Their TCR (Temperature Coefficient of Resistance) is low (<10ppm/°C) and can be controlled by selecting special wire alloys. (Usually, you need the lowest TCR, but a higher TCR has special interest in some applications.)

Continue to read here:


Riedon is ISO 9001:2008 certified company

We are pleased to announce that Riedon is now ISO 9001:2008 certificated by Det Norske Veritas (DNV).  ISO 9001:2008 registration is the most widely recognized international standard for quality management systems and is an important step in maintaining Riedon’s leadership position in the electronic components industry.

The ISO 9001:2008 defines minimum requirements for a company’s Quality Management System and many major domestic purchasers and multinational corporations require their suppliers to hold ISO 9001:2008 certification. A number significant benefits for organizations certified to ISO 9001:2008 can be realized, including a more organized operating environment and a higher level of customer satisfaction.

"ISO 9001:2008 certification is a significant step forward for Riedon and one in which our employees and management team can be justifiably proud", said Greg Wood, Vice President and General Manager of Riedon. "The Certification provides our customers with further confidence that Riedon will continue to advance their commitment to provide the highest level of customer satisfaction in all areas.”


ISO certification


Looking for IRC / TT Electronics PN: MHP140 cross?

We've heard that IRC/ITT has discontinued their MHP product line.  If you need help in crossing, please call us at 626-284-9901 or email us at  [email protected]

We have a broad selection of IRC/TT power TO type product replacement.


List Of Custom Designed Resistors

Click here to see a partial list of custom designed resistors we have done for our customers worldwide.  Click here.


customization of wirewound resistors



Low Tolerance Resistors

Looking for very low tolerance resistors, less than 0.01%?  Please check what Riedon has to offer.  Click the links below:

low tolerance resistors

Precision Wirewound Resistors

Precision Foil Resistor

Four Terminal / Surface Mount Wirewound Resistors



Call us at 626-284-9901 if you would like to talk to an application engineer.