We describe an electronic photoreceptor circuit that is sensitive to small changes in incident light intensity. The sensitivity to change8 in the intensity is achieved by feeding back to the input a filtered version of the output. The feedback loop includes a hysteretic element. The circuit behaves in a manner reminiscent of the gain control properties and temporal responses of a variety of ret...

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A time-delay chaotification approach can be applied to the Chua’s circuit by adding a small-amplitude time-delay feedback voltage to the circuit. The chaotic dynamics of this newly derived time-delay Chua’s circuit is studied by theoretical analysis, verified by computer simulations as well as by circuit experiments.

Undetectable shorts may decrease the long term reliability of a circuit, cause intermittent failures, add noise or delay, or increase test pattern generation costs. This paper describes the undetectable non-feedback shorts that are likely to occur in standard cell implementations of the ISCAS'85 combinational test circuits. For ten layouts of each circuit, all shorts between adjacent wires were...

To more thoroughly describe the system dynamics for the saccadic circuit in monkeys, we have determined the frequency response by applying a frequency modulated train of microstimulation pulses in the superior colliculus. The resulting eye movements reflect the transfer function of the saccadic circuit. Below input modulations of 5 cycles/s, the saccadic circuit increasingly oscillates with mul...

Recent experimental observations have disclosed the existence of a septal-hippocampal feedback circuit, composed of medial septum diagonal band of Broca (ms-dbB) GABAergic projections to the inhibitory interneurons of the hippocampus, and hippocampal GABAergic projections to the ms-dbB, the major targets of which are the GABAergic septo-hippocampal projection cells. We propose that this feedbac...

Engineering metabolic biosynthetic pathways has enabled the microbial production of many useful chemicals. However, pathway productivities and yields are often limited by metabolic imbalances. Synthetic regulatory circuits have been shown to be able to balance engineered pathways, improving titers and productivities. Here we developed a negative feedback regulatory circuit based on a malonyl-Co...

Quorum sensing is a chemical signaling mechanism used by bacteria to communicate and orchestrate group behaviors. Multiple feedback loops exist in the quorum-sensing circuit of the model bacterium Vibrio harveyi. Using fluorescence microscopy of individual cells, we assayed the activity of the quorum-sensing circuit, with a focus on defining the functions of the feedback loops. We quantitativel...

Multistability is a crucial recurring theme in cell signaling. Multistability is attributed to the presence of positive feedback loops, but the general condition and essential mechanism for realizing multistability remain unclear. Here, we build a generic circuit model comprising two transcription factors and a microRNA, representing a kind of core architecture in gene regulatory networks. The ...

Piezoelectric amplifier is a very important part of the piezoelectric actuator. It does not only require high positioning accuracy, but also high frequency response. This paper designs the error amplifier drive power consisting of high-voltage op amp and discrete components, consisting of an error-amplified circuit, a power amplifier circuit, a feedback network and a discharge circuit. A compen...