Resistors were first made by winding thin high resistance alloy wires on a former and then encapsulating it. This method is still used for high wattage resistors. One example is a rheostat, the other that still is used is a wire wound potenmtiometer.
Then we have carbon film, which means a very thin carbon film is coated on a porcelain/alumina/ceramic former. This is done at a very high temperature. Then using precision abrasion tools, groves are cut on in, like scratches tiil the desired resisatnce is obtained. This method is useful from 1/4 w to say 2w resistors for commercial electronics. Then a similar process for metal film resistors, greater stability and precision can be obtained with this. This MFR 1% and better is useful for Industrial and Instrumentation Applications.
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| 1/4W Metal Resistors | Riedon MFR | Resistor Networks |
Audio Gold |
LVC Ser LVC-1 | |||||||||
| Futurlec |
Riedon |
Caddock |
Ohmite |
Ohmite | |||||||||
| 1/4W Metal Film Resistors. High stability Solid construction 1% tolerance 1R to 10M |
1 Ohm to 10 Meg Ohm Tolerance to ± 0.05% Low Temp. Coeff. TC ± 3ppm/°C Very Low Inductance Matched Sets Available |
39 standard models Type 1776 precision resistor networks Absolute Tolerance Absolute T-Coeff |
3 watt to 50 watts Non-inductive available Reduces signal distortion Minimizes thermal EMI |
Standard Sizes Terminal Barrier Resists Ag Migration -55°C- +125°C Auto Insertion |
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| 1% MFR tight tolerances Highly stable low noise low temp-coeff |
demanding applications minimum tolerances long-term stability |
3, 4, and 5 – decade voltage dividers 10:1 – 10,000:1 1,200 volts continuous overvoltage to 2KV |
wire wound ceramic core high-end loudspeaker amplifier applications |
low value chip resistors current sense applications low profile, cost |
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