Abstract: A backing sheet (101) is provided with a pattern of pathways (131,132,133) of (e.g.) silica or cellulose by a printing process (e.g., screen printing). There may be multiple pathways leading from an eluant application region (117) to a detection zone (116) and thence to a waste reservoir (118). Different pathways may have different fluid traversal times because they differ in length and/or material (e.g., nitrocellulose for slow traversal and fibrous cellulose for rapid traversal by an aqueous liquid). Thus analyte and reagents deposited at depots (112,113) on different pathways are sequentially delivered to the detection zone. Reagents may be applied by printing. The detection zone may have an electrode assembly (105), also applied by printing, for detecting the effects of analyte.

Abstract: A triangle waveform generator is provided with a compensation network to eliminate the effects of frequency and amplitude errors caused by switching-control loop delays of the system. This is achieved by causing early switching of an amplitude-limit sensing detector so that the generated triangle waveform reverses polarity at the correct level. The compensation network may be implemented to accommodate independent ramp rates.