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What type of resistor technology would be best suited for a voltage divider that must be in the 10+ megaohm range that can work at a voltage of 800V+ across one resistor and have low as possible noise (used as feedback network for high voltage regulator) with a low temperature coefficient?

What techniques would minimize 1/f noise on my high voltage measurement with these resistors?

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Metal film resistors work best for lower 1/f noise. 1/f noise arises through the interaction of the carriers with grain boundaries in the bulk material. A metal film is less likely to have distinct carrier disruptions at crystal boundaries (depending upon the allotype). However, metal film resistors can have inductance, depending upon how they are made and this may not work for you. Keep in mind that a 10 MOhm resistor may have significant Johnston noise.

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Laser Printers use resonant mode DC-DC converters to regulate many high voltage outputs to the drum within 1% using either a series of precision SMT rated at 500V each or better axial resistors rated at 1600Vdc such as these. I have not seen 1/f noise dominate any of these designs as they use AGC controlled sine waves with miniature stepup-transformers to regulate the voltage using PWM to set the desired output compared to a feedback voltage ratio.

What noise level , bandwidth do you need? get?

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