FACTORS LIMITING EXTREMELY SENSITIVE MEASURING RANGES OF CONTEMPORARY PICOAMMETERS<br />
Journal Title: Metrology and Measurement Systems - Year 2007, Vol 14, Issue 4
Abstract
In the paper the principle of operation of contemporary picoammeters with analog conversion of current into voltage has been presented. The influence of factors disturbing the i/u conversion in a passive as well as in an active converter has been analyzed. It has been shown that a picoammeter with the most sensitive ranges should base on active i/u conversion. In detailed considerations maximal errors coming from internal sources (i.e. input bias current, offset, noise currents and noise voltages of ampli.er and thermal noise of a high-ohm scaling resistor) as well as external disturbances (leakage currents of printed board and insulators and disturbances in leading cables) have been discussed and evaluated. From this analysis it can be concluded that on the extremely sensitive ranges the most leading impact on the accuracy of the current measurement have the following factors: the input bias current of the electrometric amplifier, accuracy of the scaling resistor and its thermal noise. These factors limit the extremely sensitive ranges of picoammeter to the level of 10÷20 pA with an accuracy of 1.2%. The presented considerations can be helpful for designers as well as for users of extremely sensitive picoammeters because they permit to avoid some errors caused by improper configuration of the measuring circuit and to distinguish disturbances coming from different sources.
Authors and Affiliations
ZBIGNIEW KŁOS, JAROSŁAW KRYSIAK
Keywords
Related Articles
- EP ID EP107691
- DOI -
- Views 87
- Downloads 0
ANALYSIS OF THE IRREGULARLY SAMPLED SIGNALS ABOVE THE NYQUIST LIMIT
A new method of spectrum analysis of the nonuniformly sampled data above the Nyquist limit is proposed, which is based on the digital spectral shift to the baseband, optional filtering and the subsequent spectrum analysi...
THE IMPACT OF THE RANDOMIZATION OF THE QUANTIZATION ERROR ON THE ACCURACY OF MEASURING SYSTEMS APPLYING A DIGITAL MEASURING ALGORITHM
In measuring systems applying a digital measuring algorithm, the measurement process is divided into two stages: Stage 1 consists in the acquisition and storage of the system's input data, based on which the value of the...
MEASUREMENT OF LUMINESCENCE IN COLOURED PRINTED MATERIALS
While fluorescent pigments have been used for many years, the formulation and quality control of coloured printed materials containing them, has been a challenge, primarily due to lack of appropriate instrumentation at a...
MEASUREMENTS OF ROAD TRAFFIC PARAMETERS USING INDUCTIVE LOOPS AND PIEZOELECTRIC SENSORS
The basic problems corresponding to traffic measurements have been presented in the paper. The Authors gave a general overview of the parameters and characteristics describing the vehicles and traffic flow. The current s...
PROF. DR HAB. INŻ. STANISŁAW ADAMCZAK HONORIS CAUSA DOCTORATE, UNIVERSITY OF ZILINA (SLOVAKIA)
On 16 November 2007, Prof. dr hab. inż. Stanisław Adamczak, Dean of the Faculty of Mechatronics and Machine Building at the Kielce University of Technology, member of the Committee on Metrology and Research Equipment and...