Photoelectric Converter with a KDFM-Type Silicon Photodiode
Abstract Generated abstract
This paper reports an experimental study of a photoelectric measuring converter using special low-power incandescent lamps paired with KDFM silicon photodiodes as the light-sensitive element. Motivated by the limited long-term stability of available photoresistors, the authors examine current-voltage behavior under different illuminances, the converter transfer coefficient, temperature instability, and temporal instability using a specified measurement circuit. The results indicate a KDFM temperature coefficient of approximately 0.3 to 0.6 percent per degree and suggest that converters using KDFM photodiodes may offer metrological characteristics substantially better than those of conventional thermoelectric converters.
Full Text
Photoelectric Converter with a KDFM-Type Silicon Photodiode
M. S. Roitman, V. R. Tsibulsky
(Presented by the scientific-technical seminar of the Department of Radio Engineering)
The principal element determining the metrological characteristics of reference calibration and measuring AC apparatus is the measuring converter. In metrological organizations in this country and abroad, thermoelectric converters are used as such an element.
As a result of investigations carried out by the authors and E. I. Tsimbalist, photoelectric converters (PCs) based on low-power incandescent lamps and photoresistors are finding ever wider application in calibration apparatus. Unfortunately, the photoresistors currently produced by domestic industry do not possess sufficient long-term stability, which does not make it possible to realize fully the advantages of photoelectric converters. In connection with this, the search for a light-sensitive element with sufficiently high long-term stability becomes of great importance.
This article presents the results of an experimental study of PCs based on special experimental low-power incandescent lamps and KDFM photodiodes.
The investigations were carried out with the aim of studying the silicon photodiode (KDFM) as the receiver of a photoelectric converter.
The current-voltage characteristics of the KDFM for various illuminances are given in Fig. 1.
In the converter, reverse connection of the photodiode is used. The transfer coefficient of such a pair is equal to
\[ k = - \frac{\Delta R_{\mathrm{д}}}{R_{\mathrm{д}}}\cdot \frac{I_{\mathrm{л}}}{\Delta I_{\mathrm{л}}}. \]
The change in \(k\) with increasing illuminance is shown in the graph of Fig. 2.
The temperature instability (TI) of the pair is determined by two factors: the TI of the lamp and the TI of the photodiode.
The experimental setup is shown in Fig. 3.
In Fig. 4, graphs are plotted of the temperature instability of the photodiode (\(I\)) and of the pair as a whole (\(II\)). The temperature coefficient of the KDFM, according to the data obtained, is equal to
\[ R_{t^\circ} = 0.3 \div 0.6\% \ \text{deg}. \]
KDFM No. 3
\(I_{\mathrm{phd}}\) (µA)
\(U_{\mathrm{phd}}\) (V)
\(I_{\ell}=30\) mA
\(I_{\ell}=35\) mA
\(I_{\ell}=40\) mA
Fig. 1
\(K\)
\(I_{\ell}\), mA
Fig. 2
Fig. 3.
Fig. 4.
The temporal instability of the pair was determined according to the circuit shown in Fig. 3, but taking into account the instability of the power supplies \(B_1\) and \(B_2\). From the results obtained, plots of the instability of the pair with a KFDM were constructed for various illuminances (Fig. 5).
Fig. 5
The investigations carried out give grounds to believe that, in terms of their metrological characteristics, photoelectric converters with a KFDM may be substantially better than thermal converters.