Abstruct-A unified model is established for a currentprogrammed converter, which is both a modification and an extension of familiar models. Inclusion of the sampling effect allows the presence of an additional pole up in the current-loop gain to be derived. The resulting final double-slope asymptote is fixed in position, and the crossover frequency cannot exceed half the switching frequency. A stability parameter, Q 3 , determines the additional pole and describes the degree of peaking in the closed-loop transfer function. Experimental verification employs an analog signal injection technique.

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Abstract

We report the fabrication of platinum screen printed electrodes which are electrochemically characterised and evaluated as to their potential analytical application towards the sensing of hydrazine and hydrogen peroxide. In the case of hydrazine a linear range of 50 to 500 mM is possible with a limit of detection (3s) of 0.15 mM achievable using cyclic voltammetry which can be reduced to 0.12 mM using chronoamperometry. The novelty of these platinum screen printed electrodes is highlighted in that the platinum on the screen printed electrode surface resides as an oxide, which is favourable for the electrochemical oxidation of hydrazine, which need to be formed via extensive potential cycling when using a traditional platinum electrode hence the platinum screen printed sensors alleviate these requirements. The electroanalytical reduction of hydrogen peroxide is shown to be feasible with a linear range over 100 and 1000 mM with a limit of detection (3s) of 0.14 mM which is competitive with other reported analytical protocols.

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