Ohmite showcase the new alongside the old

16th October 2014

Nat Bowers

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As the company celebrates its 90^th year, the Ohmite stand will feature a blend of the old and the very new. There will be innovative heatsink designs, high energy ceramic composition resistors and surface mount current sense resistors, alongside stamps, coins, porcelain, pottery, books, a clock and a Harrods silver plated coffee pot (all from 1925).

The B60/C60 heatsinks provide designers with a variety of cooling options for up to six TO-247 and/or TO-264 devices, plus larger components. Mounting holes accommodate a standard 60x60mm fan for forced air applications when used in pairs.

The EY series of high energy ceramic composition resistors offer a 400J energy rating with 2.5W average power, making them suited to withstand single or infrequent high energy impulse events in medical devices such as defibrillators. Measuring just 46.2mm in length and 9.4mm in diameter, the non-inductive axial leaded resistors are offered in 20 standard resistance values from 10 to 100,000Ω with 10% tolerance.

Ohmite has claimed that no resistor currently available handles energy spikes of this magnitude in such a small package. The company also says that designers configuring multiple resistors to achieve the desired energy rating can now use EY resistors instead, reducing inventory, board space, manufacturing and overall cost.

The FC4L32 surface mount current sense resistor is being shown in Europe for the first time. Available in a 1206 package, the resistor uses metal foil construction, has long‐side terminals and is capable of twice the power rating of conventional chip resistors (1W power rating and handles currents up to 45A). Available in standard values of 0.001-0.050Ω (1% tolerance above 0.002Ω), the FC4L32 is capable of 45A (below 10mΩ) and 24A at or above 10mΩ, the FC4L32 has a TCR of 100ppm from 1‐3mΩ and only 50ppm above 3mΩ. Tight tolerance of 1% is standard and with Inductance values below 1.6nH (at 30MHz) it offers the kind of low‐noise performance needed in today’s high frequency applications.