  Low-frequency resistance fluctuations cause excess noise in biased resistors.
The magnitude of these fluctuations varies significantly between different
resistor types. In this work measurements of excess noise in precision thin
film and metal foil resistor networks are presented. The lowest levels were
found in metal foil devices, followed by thin film NiCr networks deposited on
silicon substrates. Higher excess noise with a significant spread between
different types was seen in thin film devices deposited on ceramic substrates.
