Diode characteristics, 222 response

To make the entire eleetronic response linear with respect to tunneling gap s, a logarithmic amplifier is attached at the output of the current amplifier. A logarithmic amplifier can be made from a feedback amplifier, by replacing the feedback resistor with a diode, as shown in Fig. 11.4. The current-voltage characteristics of a good-quality, forward-biased silicon diode follow an exponential law over more than five orders of magnitude ... 

Also Tobias et al. reported, as already described, resistivity changes to be the main reason for the hydrogen response observed in the forward direction of the /-V characteristic of Schottky diodes with a Pt gate and an interfacial layer of TaSi [78]. 

Specific detection is an analytical determination based on specific responses related to the chemical characteristics of a molecule excited by a certain type of irradiation. In this detection method, measurement of the molecule of interest may usually be performed without separation from matrix materials or from other ingredients if appropriate instrumental adjustments are made. The need for identification and structure elucidation for newly discovered compounds drives the progress of specific detection techniques with NMR and X-ray diffraction and MS. The UV-diode array detector often aids the recognition of chromatographic peak purity, ensuring complete resolution of a separation procedure. 

J.-S. Kim, H. Kajii, and Y. Ohmori, Characteristics of optical response in red organic light-emitting diodes using two dopant system for application to the optical link devices. Thin Solid FUms, 499(1-2), 343-348 (2006). 

In conclusion, Pt/4H-SiC diode rectifiers of the type used for high-power electronic applications are also shown to be effective in gas sensor Hj detection. The time response of the diodes is limited by the gas mass flow transport characteristics, with the intrinsic response due to changes in the interfacial OH-dipole layer being very rapid. 

The methodology and apparatus discussed above has been tested extensively on RC networks, and has performed very satisfactorily. Some results of this type are shown in Fig.3C and 3D. We have been able to measure RC time constants near 500 ns with 30 ns accuracy. These and other tests suggest that the instrument response function has a characteristic time that can be as short as about 30 ns, depending on the level of the current. Capacitive effects in the LED s junction region cause the response time of the diode to lengthen at reduced current levels, but a quite usable measurement system time constant was recorded even for a 20 nA current pulse, as shown in Fig.4. We have not been able to record current transients of this magnitude by any other means with a time resolution even close to that established in Fig.4. 

The AED employs a microwave-induced He plasma to dissociate eluted analyte molecules to their component atoms and excite them to emit at characteristic wavelengths. This is very similar to the mechanism in the argon plasma inductively coupled plasma source (cf. Section 7.3.1). A spectrometer with a diode array detector (Figure 7.26b and c) isolates and measures the intensity of sensitive emission lines unique to each element. Depending on the relative sensitivity and proportion of atoms in the molecules, separate element response channels may display peaks in several element-selective chromatograms. These data may be combined with retention... 

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