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P ODUCTS EVIB/V

S series

eneral

The SP series was developed using an advanced thick film printing technology. By applying this technology on a small and thin ceramic substrate, 300 to 400 mW power consumption is achieved. Combinations of new desgn, variations of sensng materials and excellent controllability have lead to improvements in sensor performance and a wide variation in the product range.

Alumina Sensng

substrate material

-J.

Heater

E E

2 mm

Eectrodes

0.3 mm Fig 13. Sensing element


	,- 100 mesh
	/ SUS 316 gauze
	("^P* "^^S^, (double)
	R>—j- Plastic housing
		\^kj Sensing element
		T" TÏÏT"^- Plastic base
		U*- Electrode and
		heater pins

Structure

The sensng material is formed on the alumina substrate on which the gold electrodes are printed. A thick film heater of ruthenium-oxide or platinum is printed on the reverse of the substrate (Fig 13). The element is installed in the plastic or mesh type housng which uses a double stainless steel mesh (100 mesh) in the path of gas flow (Fg 14: standard type). The sensor has four pins for output sgnal and heater power supply and one free pin for identification.

Fig 1 . Structure: standard type

(Top view)

Operating conditions

Fg 15a indicates the pin layout and Fg 15b shows the equivalent circuit. The standard circuit for the SP series is shown in Fg 16.

The applied heater voltage regulates the sensng element temperature to obtain the specific performance of sensors. As in the SB series, the change in sensor resistance is obtained from the change in the output voltage across the fixed or variable load resstor ( l).

3 ^---' 2

(Bottom view)

4 1

Fig 15 . E uivalent circuit

Fig 15a. in layout

Fig 16. Standard circuit emarks:

Polarity of the circuit voltage (V_C) is not important.

Standard operating conditions:

V_C: 24 V max (DC/AC) V_H: 5.0 V 4% (DC/AC) _L: Variable (P_S 15 mW) Ps = ( Vc- V l )²/ S