Response time of light emitting diode logarithmic electrometer

被引:5
作者
Acharya, YB [1 ]
Vyavahare, PD
机构
[1] Phys Res Lab, Ahmedabad 380009, Gujarat, India
[2] Shri GS Inst Technol & Sci, Indore 452003, India
关键词
D O I
10.1063/1.1148700
中图分类号
TH7 [仪器、仪表];
学科分类号
0804 ; 080401 ; 081102 ;
摘要
In a logarithmic electrometer which uses a transistor as a nonlinear element, a capacitance is generally connected across the feedback element of the operational amplifier. This stabilizes the loop but degrades the response at low current levels. However the stability problem is not so serious when a junction diode is used. In the present work an attempt was made to study the response time of a logarithmic electrometer which uses a light emitting diode (LED) as a nonlinear element and without external capacitance. The calculated values of rise time are based on an equivalent circuit with a depletion layer capacitance and voltage dependent conductance. These values are found to be in reasonable agreement with the experimentally measured values. This study will be useful in the estimation of dynamical errors in logarithmic electrometers using junction diode/LED, LED photometers and will be helpful in the techniques for improvements of the response time of logarithmic electrometers using a junction diode, particularly at low currents. (C) 1998 American Institute of Physics.
引用
收藏
页码:595 / 598
页数:4
相关论文
共 10 条
[1]   LOW-CURRENT TEMPERATURE COMPENSATED BIPOLAR LOG-RATIO AMPLIFIER [J].
ACHARYA, YB ;
TIKEKAR, SG .
REVIEW OF SCIENTIFIC INSTRUMENTS, 1993, 64 (06) :1652-1654
[2]   COMPACT LIGHT-OMITTING-DIODE SUN PHOTOMETER FOR ATMOSPHERIC OPTICAL DEPTH MEASUREMENTS [J].
ACHARYA, YB ;
JAYARAMAN, A ;
RAMACHANDRAN, S ;
SUBBARAYA, BH .
APPLIED OPTICS, 1995, 34 (07) :1209-1214
[3]   INPUT PROTECTION OF LOW-CURRENT DC AMPLIFIERS BY GAASP DIODES [J].
DAMLJANOVIC, D ;
ARANDJELOVIC, V .
JOURNAL OF PHYSICS E-SCIENTIFIC INSTRUMENTS, 1981, 14 (04) :414-417
[4]   CIRCUIT WITH LOGARITHMIC TRANSFER RESPONSE OVER 9 DECADES [J].
GIBBONS, JF ;
HORN, HS .
IEEE TRANSACTIONS ON CIRCUIT THEORY, 1964, CT11 (03) :378-+
[5]   FAST-RESPONSE APPARATUS FOR 11-DECADE LOGARITHMIC CURRENT-VOLTAGE MEASUREMENTS [J].
GRIMBERGEN, CA ;
KOHNKE, GHP .
REVIEW OF SCIENTIFIC INSTRUMENTS, 1976, 47 (07) :854-858
[6]  
Grove A.S., 1967, PHYS TECHNOLOGY SEMI
[7]   SUN PHOTOMETER WITH LIGHT-EMITTING-DIODES AS SPECTRALLY SELECTIVE DETECTORS [J].
MIMS, FM .
APPLIED OPTICS, 1992, 31 (33) :6965-6967
[8]   RESPONSE TIMES OF LIGHT-EMITTING DIODES [J].
NAKAMURA, S ;
UMEDA, JI ;
NAKADA, O .
IEEE TRANSACTIONS ON ELECTRON DEVICES, 1972, ED19 (08) :995-+
[9]   CARRIER GENERATION AND RECOMBINATION IN P-N JUNCTIONS AND P-N JUNCTION CHARACTERISTICS [J].
SAH, CT ;
NOYCE, RN ;
SHOCKLEY, W .
PROCEEDINGS OF THE INSTITUTE OF RADIO ENGINEERS, 1957, 45 (09) :1228-1243
[10]  
SZE SM, 1969, PHYSICS SEMICONDUCTO