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A study was conducted to determine the usefulness of discontinuous single-electrode voltage-clamp (DSEVC) amplifiers in measuring gap junction conductance. Results indicate that ordinary DSEVCs will provide inaccurate measurements brought about resistance series problems. However, if they will be designed with proportional-and-integral voltage-clamp circuits, they will give accurate gap junction conductance. With these circuits, the DSEVCs will not be affected by series resistance and membrane resistance.

This paper describes a direct-linked-type frequency changer (DLT-FC) proposed by the authors. The DLT-FC is a converter circuit with a new configuration for direct frequency change. The DLT-FC does not require a dc-link circuit, nor bilateral switches. In addition, dc snubber circuits can be applied without the need for a regenerative circuit of snubber energy. Therefore, the DLT-FC can be designed to be compact and lightweight, and have a long life. The authors made a prototype of the DLT-FC and experimentally checked its operation. The results indicate that the performance of the DLT-FC makes it suitable for industrial use. Index Terms - Direct-linked type, frequency changer, matrix converter, snubber circuit.

A growing number of experimental studies have used patch-clamp amplifiers (PCAs) in the current-clamp (CC) mode to investigate classical excitability. In this paper we show that the measurements obtained in this way are affected by errors due to the electronic design of the PCA input section. We present experimental evidence of such errors, and demonstrate that they derive from PCA current absorption. Moreover, we propose a new PCA input-circuit configuration for the CC mode, which is suitable for accurately recording physiological voltage signals and is perfectly compatible with the standard voltage-clamp mode.

Flyback derived topologies are attractive because of their relative simplicity when compared with other topologies used in low power applications. Incorporation of active-clamp circuitry into the flyback topology serves to recycle transformer leakage energy while minimizing switch voltage stress. The addition of the active-clamp circuit also provides a mechanism for achieving zero-voltage-switching (ZVS) of both the primary and auxiliary switches. ZVS also limits the turn-off di/dt of the output rectifier, reducing rectifier switching losses, and switching noise due to diode reverse recovery. This paper analyzes the behavior of the ZVS active-clamp flyback operating with unidirectional magnetizing current and presents design equations based on this analysis. Experimental results are then given for a 500 W prototype circuit illustrating the soft-switching characteristics and improved efficiency of the converter. Results from the application of the active-clamp circuit as a low-loss turn-off snubber for IGBT switches is also presented.

This paper presents an alternative circuit configuration for clamping the link voltage in a resonant dc-link converter. The alternative circuit is a lossless clamp which allows for totally autonomous control of the clamp voltage and resonant link under all operating conditions. The clamp is comprised of two capacitors, three controllable switches and three diodes. The clamp does not require the use of external bias supplies for startup or no-load operation. Control of the input and/or output waveforms for a converter employing this circuit remains virtually identical to that for the resonant dc-link inverter (RDCLI). An analysis of clamp operation is performed detailing its modes of operation. From this analysis, insight is gained into the appropriate selection of clamp capacitors. Simulations and experimental results are presented to corroborate the analysis. The control of the clamp is discussed in detail.

The conventional diode clamping inverter suffers from such problems as dc !ink unbalance, indirect clamping of the inner devices, turn-on snubbing of the inner dc rails as well as series association of the clamping diodes etc. It is due largely to these problems that the application of the conventional diode clamping inverter in practice has been deterred, in spite of the growing discussion in the literature. The paper proposes a new diode clamping inverter, which works without the series association of the clamping diodes. An auxiliary resistive clamping network solving the indirect clamping problem of the inner devices is also discussed for both the new and conventional diode clamping inverter. Operation principle, clamping mechanism, auxiliary clamping as well as experimentation are presented. Index Terms--Multilevel inverter.

Detailed analysis and parameter design for a resistor-capacitor-diode (RCD) clamped snubber used in the output rectifier of phase-shift full-bridge zero-voltage-switching (PS-FB-ZVS) converters are presented. Design equations and some properties of the clamped circuit are highlighted. Index Terms - Phase-shift full-bridge zero-voltage-switching converters, snubber.