Thermal Transient Measurements of an Ultra-Low-Power MOX Sensor

Figure 5

Heating phases at regime: measured responses obtained applying a periodic PWM stimulus with different ${\tau }_{\text{PWM}}$ periods. In each heating cycle, heating was stopped when a target value $R_H$ = 200 Ω was reached. Ambient temperature T_a = 27°C. Heating pulse period ${\tau }_{\text{PWM}}$ = 50 $\mu$s (a), ${\tau }_{\text{PWM}}$ = 200 $\mu$s (b), ${\tau }_{\text{PWM}}$ = 1 ms (c), and ${\tau }_{\text{PWM}}$ = 5 ms (d). Dashed lines show an imaginary and rectified cooling transient that was not directly measured.

(a)

(b)

(c)

(d)