Adjustable resistors handle higher temperatures

High-specification devices target the need for precision and accuracy in extreme temperature environments and offer a lifetime drift of far less than 1%.

Microbridge Technologies has released three new Rejustor devices that extend the company's reach into the high-temperature, military/aerospace and energy exploration markets.

Available in two basic types, the Rejustors target the need for precision and accuracy in extreme temperature environments and offer a lifetime drift of well less than 1%.

The new Rejustors have no mechanical moving parts and are ideal for vibration-sensitive applications such as calibrating electronics for Jet engine monitoring instruments, voltage regulators, down-hole drilling, military, furnace and boiler, strain gauge and vibration sensors.

These applications benefit from improved reliability, dependability, dust and moisture resistance over mechanical parts as well as from the lowest noise and widest bandwidth of any adjustable resistor technology available.

"These three new high temperature Rejustors from Microbridge offer precision and accuracy performance levels that have previously not been achievable", says Felix Levinzon, Principal Engineer at Endevco.

"The long-term resistance stability of individual Rejustors is better than 1%, up to thousands of hours at 225C.

We are pleased to have helped Microbridge characterise many of its high temperature devices".

"HT-Rejustors also set new, lower price points and provide the ability to easily adjust circuit parameters for aging effects years after the product has been deployed", says Bob Frostholm, Vice President of Marketing at Microbridge.

"They are especially suitable for downhole exploration because as oil and gas reserves are getting more difficult to find, more sophisticated and accurate equipment is needed to locate these smaller reserves".

Each resistor element is independently electrically adjustable to any value from its nominal, down to 80% of nominal value.

The MBH-273-AS1 (Type I Rejustor) is a pair of nominally 27kohm Rejustors and offers a precision adjustment of better than 0.1% while maintaining a +/- 2.5% tolerance over the entire operating temperature range of -55 to +230C.

Type II Rejustors are designed to offer superior resistance tolerances of +/-0.7%: "tuned" for a narrower 50C "window" or band within the high temperature operating range.

MBH293-AS2, for example, has a pair of nominally 29kohm Rejustors that can be acquired as a Type IIA, offering 0.7% tolerance between 150 and 200C, or as a type IIB, offering the same 0.7% resistance tolerance over the 175 to 225C range.

HT-Rejustor dividers are temperature stable so that the ratio between the two resistors is predictable within +/-1% regardless of adjustment state of either HT-Rejustor, as long as both HT-Rejustors are at the same temperature.

Precision resistance adjustment of each HT-Rejustor is accomplished by changing the physical properties of the resistor under control of Rejustor Calibration tools and Rejust-it software.

The adjustment process is typically complete within 1-2s.

Available directly from Microbridge, the MBH-273-AS1 Type I is priced at US $6.95 for quantities of 1000.

The MBH-293-AS2 Type IIA is priced at US $7.64 per 1000 pieces, and the MBH-293-AS2 Type IIB is priced at US $8.34 per 1000 pieces.

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