Piezoresistive effects in thick-film resistors

Piezoresistive properties of thick-film resistors obtained with ink series supplied by different manufacturers have been investigated as a function of composition, structure, sheet resistivity, and applied strain between 0 and ±1000 μ strain. The strain sensitivity of thick-film resistors appears to be a strong function of the nature of the conductive grains and of the sheet resistivity of the paste; the results obtained suggest a dominant role of the tunneling effect in the conduction mechanism and in the strain sensitivity.