Main parameters of cermet and polymer thick film resistors

The most important parameters of a thick film resistor are as follows:

- nominal value of the resistance, which usually falls in the range of 1 ohm to 10 Mohm;

- sheet resistance (r or R-square), where r = p/t, the ratio of specific resistance (p) and thickness (t);

- temperature coefficient of resistance, TCR, where TCR = dR/dT, or in the technical usage TCR = (R2-R1)/R1/(T2-T1);

- thermal mismatch of TCR, that is the difference of temperature coefficients of resistance of resistors on the same substrate;

- adjustable tolerance, which is the accuracy of the resistance that can be achieved, highly depending on the resistor geometry and the stability;

- power density, the admissible power dissipation of the surface unit of a resistive layer;

- stability, the admissible change in the resistance value under defined loading conditions.

A thick film circuit with integrated resistors and hybrid components