High-dynamic Ammeter with Small Time Constant

Simple SummaryContent extracted from patent full text and abstract with AI.

The invention concerns a high-dynamic ammeter (current measuring device) with a very small time constant for rapid and precise measurement of electrical currents, even as they change quickly over a wide range of values. It describes two types of ammeters based on operational amplifiers configured as current-to-voltage converters, with smartly modified feedback resistors. The first ammeter automatically and nearly instantaneously switches its measurement range in response to the current, providing multiple outputs of different sensitivities if needed. The second uses diodes as part of the feedback, creating a logarithmic response with tunable sensitivity. These approaches can be combined within one instrument for optimal performance.

Use CasesContent extracted from patent full text and abstract with AI.

• Scientific instruments such as scanning tunneling microscopes or nano-electrodes, where currents can change by many orders of magnitude very quickly.
• Precision measurement in electronics testing and research, especially where high dynamic range and fast response are necessary.
• Industrial quality control for components requiring fast and accurate current measurements over a broad range.
• Electrochemical analysis, such as in potentiostats for studying chemical reactions or sensor development.
• Biomedical research where recording tiny, fast-changing electrical signals is crucial, such as neural activity measurements.

BenefitsContent extracted from patent full text and abstract with AI.

• Extremely wide dynamic range allows accurate current measurement from fA to mA levels without losing resolution.
• Very fast automatic range switching (less than 0.1 milliseconds), minimizing dead time and avoiding loss of signal.
• Multiple parallel output channels with different sensitivities can be recorded simultaneously, simplifying calibration and increasing measurement confidence.
• Combination of linear and logarithmic modes in one device provides both high sensitivity and wide range within a single instrument.
• Electronic (not mechanical) switching and calibration features reduce size and complexity, allowing for integration into compact or portable devices.
• Improved suppression of errors due to leakage currents and parasitic capacitance leads to more stable and reliable measurements.

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Patent Abstract

The invention provides two different ammeters which in their core are based in each case on an operation amplifier connected as current voltage converter. The particular advantages of the instruments according to the invention with respect to generic instruments can be found in each case in a target-directed modification of the circuitry resistor in the feedback path. In the instrument according to the main claim ("instrument 1"), the circuitry resistance changes as a function of the current to be measured. Instrument (1) is thus a linear amplifier with automatic, quasi-instantaneous measurement range switching, optionally also with multiple output channels with different sensitivities which can be recorded simultaneously. In the instrument according to the subclaim ("instrument 2"), the circuitry resistor comprises at least two biased diodes. Instrument (2) is thus a logarithmic amplifier with a sensitivity which can be adjusted by way of the bias. The advantages of instruments (1 and 2) can be intercombined as desired in an instrument because they are technically related.