ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
The current–voltage characteristics of logarithmic amplifiers depend considerably on the ambient temperature. A theoretical correction has been estimated considering the temperature dependence of various parameters in the diode equation. A log electrometer using light-emitting diodes has been fabricated and its I–V characteristics are obtained experimentally for calibration and also to determine the device constant. If a measurement is obtained at a temperature other than the one for which calibration has been done, the theoretical correction can be applied to get the correct value. It has been shown that the theoretically corrected readings lie within ±4% of the experimentally obtained data in the temperature range of 5–60 °C for the operating current range of 10−12–10−4 A. The alternative can be to introduce temperature compensation circuitry into the logarithmic amplifier. However, this makes the electrometer circuit more complex. The proposed theoretical correction method may find applications where space and power are at a premium and the accuracy requirement is not very stringent. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1147002
