Riedon’s precision resistors are designed for critical applications that require very accurate and stable resistance values. Precision resistors are normally specified when the wattage requirements are relatively low, and when high accuracy and stability are necessary. They are available in a subminiature series, the standard 100 series, and special low-reactance version for fast rise time applications.
These precision resistors are non-inductively wound on molded bobbins. The solderable and weldable leads are tinned copper. Internally, they are welded for highest precision and reliability. All precision resistors are aged to insure stability. A protective coating insulates the windings and protects the welds. The bobbin is encapsulated using a specially formulated epoxy so temperature expansion coefficients of all materials are closely matched.
When modern circuits need power resistors, the choice is often wirewound. Today's wire-wound resistors are rugged and reliable. They are small and compatible with modern PC-board and surface mount manufacturing systems. And, new technology resistors still fall short of wire-wounds. Look at the chart: although metal foil technology is a close second to wirewounds, other technologies are generally unable to measure up in power rating, tolerance and TCR.
From Joule-rated devices for energy absorption to
miniaturized components for current temperature
sensing, wirewound resistors continue to offer
significant advantages over alternatives in many
click here to see our published whitepaper for high pulse/ Joule rate resistors.
After years of comprehensive test & evaluation, Riedon's custom designed resistor has been selected in a proximity sensor product line which will be used on the Boeing 737 NG (Next-Generation) family of aircraft .
These sensors are used in various applications including landing gear, doors, and flight controls.
The 737 NG is part of the 737 family which has been the most successful commercial aircraft of all time with over 10,000 aircraft delivered or on order.
The 737 represents more than 25% of the worldwide fleet of large commercial jet airliners.
Riedon's non-magnetic resistors like our CBR series and CHR seriesare appropriate for Medical applications such in the field of magnetic-resonance (MRI) and computer tomography (CT), where electronic circuits are located in high magnetic fields. The resistor contact areas do not contain Nickel, they are made of metal alloys based on PtAg and PtPdAg, and available as thick film pastes, which are applied by roller-coating or dipping processes onto the wrap-around areas of the chip components and fired in the range of 850ºC.
The standard SMD soldering processes can be used, but these resistors are also suited for contact processes using silver-based conductive epoxy. The contact-technique of conductive epoxy is used mainly in applications where soldering techniques cannot be applied by technical reasons like the usage of temperature-sensitive components which would be affected by high soldering temperatures, or the usage of unpackaged semiconductors on the same board.
Also, another advantage of our non-magnetic thick film chip resistors with PtAg or PtPdAg contacts is suitability for applications at higher temperatures than the typical maximum temperature of 155ºC. These resistors contain no organic material and no tin or tin-lead layers, and the firing temperatures for the resistive and conductive layers are in the temperature range of 850ºC. Due to these reasons such resistors will have no substantial change of their properties and stability all the way up to 300ºC.
Riedon, a specialist manufacturer of cutting-edge resistive solutions, is pleased to announce the hiring of Greg Wood as the new Senior VP and General Manager, effective from January 2, 2014. Greg will report to Riedon owners, Michael Zoeller and Duane Ebbert.
Greg has a BSBA in Production and Operations Management from San Diego State, an MBA from the University of Redlands and comes to Riedon with experience and a proven track record of success in the management, development and manufacture of technical products. Greg’s most recent manufacturing position was as President and CEO of Surfx Technologies, a manufacturer of atmospheric plasma systems for the medical device, semiconductor, aerospace and industrial markets. Prior to Surfx, Greg was the President, CEO, and CFO of Emergent Respiratory Products, a medical device company. In an earlier position, Greg was President and CFO of American Microwave Technology, an RF power amplifier manufacturer.
WELCOME ABOARD GREG!
High performance resistors are key to meeting the demanding requirements of portable medical electronics designs
Medical 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.
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Riedon is targeting the demanding requirements of current sensing and shunt applications with its comprehensive portfolio of low ohmic value resistors, ranging from the economical bare metal element MSR series through to its CLSA series chip resistors that provide AEC-Q200 compliance for use in harsh automotive environments.
Utilizing various technologies, Riedon offers ±1% tolerance resistances from 0.5 milliohms up to 1 ohm in various package formats with TCRs as low as ±20ppm/oC and power ratings up to 5 Watts. For tolerances down to ±0.1%, Riedon is also able to supply four terminal versions of its axial lead low ohm power resistor.
The MSR series uses a bare metal element in an all-welded construction for through-hole circuit board mounting to provide resistance values from 5mΩ to 100mohm, while also achieving low inductance (<10nH) and low TCR (±20ppm/C). MSR resistors are available in 1W, 3W and 5W power ratings with tolerances of ±1% or ±5%. For surface-mount applications, the company offers several chip resistor solutions: its MNRS chip shunt resistors offer exceptional long-term stability and low inductance with 4W and 6W ratings and resistances from 1mohm to 4mohm; the CSR family of ultra low ohm metal strip chip resistors come in three sizes (1206 / 2010 / 2512) for power ratings from 1W to 3W, with standard and customized resistance values from 0.5mohm to 15mohm; and featuring an alumina substrate for high power dissipation the CLS/CLSA series of chip resistors operate over -55C to +155C, with the CLSA parts meeting the Automotive Engineering Council’s AEC-Q200 stress test qualification, says the company.
“Current sensing applications insert a low ohmic precision resistor in series with the load current, creating a small voltage drop that can be readily measured and used to calculate the current flowing through the resistor”, explains Phil Ebbert, Riedon’s VP of engineering, “Resistance values of just a few milliohms allow currents of several Amps, even tens of Amps, to be handled with device power ratings up to 5 Watts. Riedon’s capability to produce such low ohmic values, with well defined tolerances, enables it to serve a wide range of current sensing and shunt resistor applications.”
When comparing thin film and thick film resistors, thin film resistors are able to achieve much lower tolerances and resistor temperature coefficients, have lower noise, lower parasitic inductance, and lower capacitance. With these better qualities, thin film resistors have generally been much more expensive to produce than their thick film resistor cousins, however, improvements to mass production techniques and operation conditions have greatly reduced the cost to manufacture high-quality, precision thin film chip resistors. Riedon’s CAR series resistors are available with tolerances to ±0.01% and temperature coefficient ratings to ±25 ppm/°C at a fraction of the price of the typical thin film chip.
Here are some applications where these thin-film resistors make sense for use:
Instrumentation - Aircraft instruments, altimeters, gauges, flight control systems.
Medical - Heart monitors, diagnostic equipment, scales, scopes.
Audio - Radio receivers, DVD/Blu-Ray players, amplifiers, tuners, equalizers, crossovers.
Computer - Voltage regulators, voltage dividers, network communications, process controllers.
Power Suppliers - Step-Up or Step-Down converters, input or output voltage sets, voltage dividers.
Telecom - Voice communications, routers, bridges, multiplexes, fiber/wire converters.
HVAC – AC, ventilation, heating control.
RF – Wireless routers, Bluetooth modules, cell phone receivers, display drivers.
High Ohm Resistors In A Small Package Size When trying to analyze very low electronic signals, a stable, high ohm resistor is required. With thick film technology, very high values (up to 10 Tera-Ohms!) can be achieved in smaller and smaller package sizes. With thick films, the conduction mechanism is a combination of metallic and semiconductor conductivity and a mixture of metal and glass/organic binders is screen-printed onto a ceramic base and then fired at 850°C. A precise mixture of these particles will yield a resistor that is not only very stable, but also has quite low temperature coefficient (TCR) and voltage coefficient (VCR) ratings.
The resistors then utilize laser-cut trimming to make the resistor value as precise as possible, and tolerances down to 0.5% can be achieved, depending on how high the ohmic value is.
Check out Riedon's HVC Series with resistance ranges from 10 Mohm to 1 Tohm in package sizes as low as 0402. Click here.
Or for higher-temperature and/or higher voltage applications, our HVS series is also available with an operating temperature up to 300°C. Click here.