Operational amplifier potentiostats employing positive feedback for IR compensation.  I.  Theoretical analysis of stability and bandpass characteristics

Brown, Eric; Smith, Donald E.; Booman, G. L.

doi:10.1021/ac60266a024

Cited by 124 publications

(42 citation statements)

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“…G. Booman and coworkers published a series of papers on IR drop in three-electrode cell configurations, and on compensation thereof using a potentiostat with positive feedback [32]. More recently it was shown that the effect of the uncompensated resistance can be quantitatively described for a uniform distribution of the potential over the surface of the working electrode [33].…”

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confidence: 99%

On “resistance overpotential” caused by a potential drop along the ultrathin high aspect ratio gold nanowire electrodes in cyclic voltammetry

Muratova

Mikhelson

Ermolenko

et al. 2016

J Solid State Electrochem

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High aspect ratio ultrathin (d10 nm) gold nanowires deposited on Si/SiO2 substrate are used as working electrodes for measuring cyclic voltammograms (CVs) in aqueous solutions of ferrocene methanol and potassium hexacyanoferrate(III). The broadening of the peak separation as compared with that at a solid working electrode is explained as a result of the potential drop ("resistance overpotential") along nanowires and nanowire network. The change in the CV shape over a sequence of scans is ascribed to a gradual breakup of individual nanowires and the respective transition of the linear diffusion to hemispherical diffusion regularities.

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mentioning

confidence: 99%

On “resistance overpotential” caused by a potential drop along the ultrathin high aspect ratio gold nanowire electrodes in cyclic voltammetry

Muratova

Mikhelson

Ermolenko

et al. 2016

J Solid State Electrochem

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“…The ac and the two dc input signals to the potentiostat are generated by the frequency synthesizer FS and the two digital to analog converters DAC. The sum of these input signals is applied to the cell via the potentiostat P, built in this laboratory following the design of Brown et al [ 20]. The connections between cell and potentiostat axe made via switches in such a way that it is possible to replace the cell by a dummy resistor R. These switches can be operated automatically with the aid of a relay actuator RA.…”

Section: (Ii 1) Parts Of the Set-up And Their Arrangementmentioning

confidence: 99%

A high-precision network analyzer system for the measurement of the electrode impedance of both stationary and non-stationary electrode, with special attention to the dropping mercury electrode

Bongenaar

1980

Journal of Electroanalytical Chemistry

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A largely automatic instrument for the measurement of the admittance of a galvanic cell is described. During a measurement the frequency of the alternating voltage and the dc voltage are scanned stepwise in a programmed sequence. A high precision has been obtained by applying a programmed correction procedure and an automatic correction for short-term drift.The performance of the instrument is demonstrated on a dummy cell, a cell with supporting electrolyte only and on the determination of the kinetic parameters of the fast Cd(II) ion reduction on the DME in 1 M KC1. (I) INTRODUCTIONIn the past the impedance method has proved to be a powerful method for the study of electrochemical cells. The method may be applied for several purposes, e.g. characterization of an electrochemical object to find possible mechanisms in electrochemical processes, or in electroanalytical chemistry. In the last two cases the electrochemical object is mostly the dropping mercury (DME), because of its advantages of reproducibility and relative chemical inertness.When accurate measurements were required, ac bridges [ 1--4] were long considered to be superior to direct-measuring, phase-sensitive devices [ 5--11 ]. However, the (manual) operation of an ac bridge is tedious and time-consuming, especially in the case of a non-stationary object. In particular, in studies of electrode processes, it is increasingly recognized that many data points are needed, in both a wide frequency and a wide dc potential range, in order to be able todistinguish the possible contributions of charge transfer, diffusional mass transport, coupled chemical reactions and adsorption phenomena. It is therefore understandable that in recent developments much effort has been devoted to design more or less automatically operated, directmeasuring devices. For example, Huebert [ 12], using several tuned amplifiers, was able to apply a number of frequencies simultaneously to the cell, but still

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“…The amount of error that is conveniently observable in experimental testing should also be considered. A further fact to be considered is that a greater degree of damping (less overshoot) will generally be observed in the presence of faradaic reactions than in their absence, for the same controller characteristics (24,34). Finally, it should be recognized that the transient response of the system when control is first initiated may be different from that observed when the steady-state system is perturbed by a step function.…”

Section: Specifications and Criteria For Tuning The Potentiostat-cellmentioning

confidence: 99%

Application of direct digital control of electrode potential to controlled-potential electrolysis experiments

Pomernacki¹,

Harrar²

1975

Anal. Chem.

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A mlnlcomputer program and electronlc hardware have been developed for controlllng the potentlal of an electrode through the medlum of an algorlthm wlthln the computer. The control algorlthm found to be satlsfactory Is the dlscrete equlvalent of proportlonal-plus-Integral actlon. Control func= tlone are carrled out In assembly language at a sampllng rate of 1 kHz; the parameters that govern the control actlon and electrolysls condltlons can easlly be changed on-llne vla a hlgh-level conversatlonal language. Theory has been developed for guidance In tunlng the controller for varlous electrolysls cell characterlstlcs. Detalled control obJectlves and speclflcatlons have been formulated for typical electrolysls experlments. The system has been tested wlth mercury-pool and platlnum worklng-electrode cells, demonstratlng that the control objectives can be met and that the theory Is useful. System rlsetlmes of lese than 8 msec can be achleved, and steady-state control errors are not slgnlflcant. A malor fractlon of the tlme durlng each sampllng perlod ls available for other data processlng.The direct digital control (DDC) of the potential of the working electrode in a 3-electrode cell has been viewed as an interesting possibility (1, 2 ) ever since the advent of minicomputers. In contrast to computer-controlled potentiostats (see, for example, Refs. 1-61, where the feedback control is still accomplished by means of an analog potentiostat, DDC of the electrode potential is a concept in which the control action is generated by means of a computational algorithm within the computer. This approach is also different from the type of digital control described by Goldsworthy and Clem (7, 8) and White (9), in which the control is effected through measurement of the electrode potential by means of a differential comparator, followed by a digital output. In their technique, which does not involve the use of a computer, the control action and its characteristics are fixed in hardware.Direct digital control via software has been widely implemented in industrial process control (10-121, but for a number of reasons has not yet found application in electrochemistry. One reason has been that a speed of response comparable to that of analog circuitry could not be attained because of computational speed limitations in the computer. Now, however, the existence of faster minicomputers, digital multiply/divide circuits, and advanced software techniques have enabled significantly faster data processing. At the present time, DDC would appear to be practical at least for laboratory-scale controlled-potential electrolysis, and possibly analytical voltammetry, because these techniques do not require very high control speeds.A second factor hindering the development of DDC in the laboratory has been the much greater cost of the digiAuthor to whom correspondence should be addressed.tal, compared to the analog approach. However, when the ubiquity and versatility of the minicomputer is considered, the use of DDC can be regarded much more favorably. ...

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Operational amplifier potentiostats employing positive feedback for IR compensation. I. Theoretical analysis of stability and bandpass characteristics

Cited by 124 publications

References 13 publications

On “resistance overpotential” caused by a potential drop along the ultrathin high aspect ratio gold nanowire electrodes in cyclic voltammetry

On “resistance overpotential” caused by a potential drop along the ultrathin high aspect ratio gold nanowire electrodes in cyclic voltammetry

A high-precision network analyzer system for the measurement of the electrode impedance of both stationary and non-stationary electrode, with special attention to the dropping mercury electrode

Application of direct digital control of electrode potential to controlled-potential electrolysis experiments

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