I need non reactive resistors for use at LF thru HF (100KHz thru 30MHz) for use with radio receiving antennas as terminations. Carbon comp and carbon film work but have their shortcomings in stability and TCR. Thin film resistors have low or no inductance but they are expensive. Wirewound have poor frequency response. What other type resistors are suitable?
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3\$\begingroup\$ So we can provide more useful answers: Surface-mount, through-hole, or chassis-mount? What sort of power ratings? \$\endgroup\$– user2943160Commented Jun 24, 2016 at 0:35
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1\$\begingroup\$ Also, what are your targets for the specs you did mention (stability, TCR, inductance)? \$\endgroup\$– The PhotonCommented Jun 24, 2016 at 1:13
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2\$\begingroup\$ If the power is low <1W, you can get away with large SMD resistors, these are usually thin film but are quite cheap \$\endgroup\$– SamCommented Jun 24, 2016 at 1:46
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\$\begingroup\$ More precisely the resistors are used as terminations for outdoor receiving pennant antennas. My focus has been on axial leaded parts and no power is being dissipated. The key performance characteristic is non reactive. \$\endgroup\$– mwdxerCommented Jun 25, 2016 at 15:44
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\$\begingroup\$ From resistorguide.com.... Wire wound 0.3 - 56uH Foil < 0.8uH Metal Oxide 3-200 nH Film <2 nH \$\endgroup\$– mwdxerCommented Jun 29, 2016 at 13:20
2 Answers
For your application I would suggest the use of Metal foil Resistors.A specific foil alloy with known and controllable properties (Ni/Cr with additives) is applied to a special ceramic substrate, resulting in a thermo-mechanic balance of forces. A resistive pattern is then photo-etched in the foil. This process uniquely combines the important characteristics of low TCR, long-term stability, non-inductance, ESD insensitivity, low capacitance, fast thermal stabilization, and low noise in one single resistor technology.
These include low tempco (0.05 ppm/°C ), tolerances as low as ±0.005% (down to ±0.001% when hermetically sealed), load-life stability of ±0.005% (50 ppm) with an ESD immunity up to 25 kV.
Check the link for more info http://www.vishaypg.com/foil-resistors/
Note: 30 MHz is not really considered a high frequency
Foil Resistors may be an overkill for your application . They are expensive. Precision thin film resistors may be good enough. Here is a general comparitive table for your reference
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\$\begingroup\$ How would your resistors perform at high values and high voltages where parasitic capacitance could be an issue ? \$\endgroup\$– AutisticCommented Jun 24, 2016 at 21:35
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\$\begingroup\$ As a note, <30MHz is known as "high frequency (HF)" to amateur radio operators. Ancient terminology, but still what us hams use today. \$\endgroup\$ Commented Jun 25, 2016 at 2:11