Current Noise of Resin Type and Cermet Type Thick Film Resistors

The current noise indices (C.N.I.) depend linearly on the logarithmic values of sheet resistivity (log⁡ ρ S ), in both carbon black/resin and thallium oxide/glass resistors, and can be expressed as C.N.I. = A + B log⁡ ρ S . The geometrical dependency on C.N.I. in both types of resistor can be expressed as C.N.I. = A ′ − B ′ log⁡ ( L , W , T ), where A , B , A ′ and B ′ are constants. The dependency of noise e.m.f. ( ν n ) on the applied dc voltage (V), i.e., the values of α in , can be obtained from the slope of C.N.I. versus log⁡ ( L ) lines, associated with a model based on the noise generator approximation.