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Mechanistic Analysis
Published in Ramanathan Srinivasan, Fathima Fasmin, An Introduction to Electrochemical Impedance Spectroscopy, 2021
Ramanathan Srinivasan, Fathima Fasmin
For a set of kinetic parameters, the fractional surface coverage of Aadsvs. Edc is shown in Figure 5.7a, and the idcvs. Edc curve is shown in Figure 5.7b. The kinetic parameter values are given in the figure caption. The complex plane plots of the impedance spectra at two different dc potentials are shown in Figure 5.7c and d. The low-frequency impedance of the data presented in Figure 5.7d shows negative values, and the physical meaning of this needs to be explained. We remind the reader that the impedance discussed here is the differential impedance, which means that if the slope of the idcvs. Edc plot is negative, then at low frequencies, a negative differential impedance, sometimes called negative impedance or negative resistance, would arise. Note that here negative resistance does NOT mean that if we apply a dcpotential, then the dc current will flow in the opposite direction. The meaning of the negative resistance is that if we increase the potential, then the current will decrease, but it will continue to flow in the same direction.
I
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
immediate addressing an addressing mode where the operand is specified in the instruction itself. The address field in the instruction holds the data required for the operation. immediate operand a data item contained as a literal within an instruction. immersed flow a flow of electrons emitted from an electron gun exposed to the focusing magnetic fields. immittance a response function for which one variable is a voltage and the other a current. Immittance is a general term for both impedance and admittance and is generally used where the distinction is irrelevant. immunity to a distrubance an equipment or systems capability to operate if an electromagnetic disturbance occurs. impact excitation excitation of an atom or molecule resulting from collision by another particle such as an electron, proton, or neutron. IMPATT diode acronym for impact avalanche and transit time diode. Negative resistance device used at high frequencies used to generate microwave power. Typically used in microwave cavity oscillators. impedance (Z) (1) electrical property of a network that measures its ability to conduct electrical AC current for a given AC voltage. Impedance is defined as the ratio of the AC voltage divided by the AC current at a given point in the network. In general, impedance has two parts: a real (resistive) part and an imaginary (inductive or capacitive "reactive") part. Unless the circuit is purely resistive
RFIC Parametric Converters: Device Modification, Circuit Design, Control Techniques
Published in Krzysztof Iniewski, Wireless Technologies, 2017
Sebastian Magierowski, Howard Chan, Krzysztof (Kris) Iniewski, Takis Zourntos
An idealized schematic of a one-port negative-resistance amplifying circuit is illustrated in Figure 17.1; here RA effectively reduces the generator resistance, hence boosting the power available from the source. A variety of diode structures can be configured for negative-resistance amplification. In this case, an external DC power bias can alter the internal device structure in such a way that a higher signal current can flow through the element for a lower energy penalty. A number of physical principles can be exploited to achieve this behavior. For example, in tunnel diodes the negative resistance is achieved on an essentially quantum mechanical level (the variation of resonant energy states based on changes to energy-band distribution). Although capable of high-speed operation, this approach is largely limited to specialized applications for a variety of reasons including difficulty of integration, cost, poor efficiency, and cumbersome biasing requirements.
Systematic realisation of inductorless and resistorless Chua’s chaotic oscillator using VDGA
Published in International Journal of Electronics, 2023
Chandan Kumar Choubey, Sajal K. Paul
The traditional Chua’s chaotic oscillator, as shown in Figure 1 of Kennedy (1992), consists of mainly two sections: (a) tank oscillator with coupled network (section consists of L, R, C1, and C2) and (b) nonlinear resistor (NR). The parallel combination of the inductor (L) and capacitor (C2) realises the tank oscillator, whereas the resistor R and capacitor (C1) realise the coupled network section of Chua’s circuit. The nonlinear resistor, also called Chua’s diode, is a piecewise linear negative resistance. Chua’s diode is the main element of Chua’s chaotic oscillator as it introduces the nonlinear properties in the system. One of the most popular methods to implement a Chua’s diode is connecting two voltage-dependent Negative Resistances (NRs) in parallel (Kennedy, 1992). The dynamics of a third-order Chua’s chaotic oscillator is governed by a set of differential equations as given in equation (1) of Kennedy (1992).
Impact of variable negative solar resistance: modified virtual feed forwarded with feedback emulated inertia controller
Published in International Journal of Ambient Energy, 2022
Normally, the nonlinearity of the I-V curve causes the desired output to differ according to the dynamic resistance operating point. The negative resistance derived from the I-V curve reflects the nonlinear effect and varies with the voltage as the irradiance and temperature changes of the PV cell. The nonlinear effect has increased in significance owing to the influence of the system's stability. In several kinds of literature, the effect of negative resistance on boost converter has been addressed (Badini and Verma 2020). The negative resistance is attached in the voltage transfer function. The system is easy to regulate for second-order controller without any negative impact on regulatory performance (Li et al. 2020). The PV voltage is normally regulated through an inner inductor current loop for power boost converter. The cascaded system eliminates the transient current and reduces the failure rate (Cheng et al. 2020). The effect of dynamic resistance in the system makes the voltage regulation slower than the design requirements, particularly when small input capacitors are used.
A 24 GHz frequency synthesizer for automotive collision avoidance radar
Published in International Journal of Electronics Letters, 2020
The current-reuse VCO requires less power for starting up the oscillation compared to traditional cross-coupled VCO. In current-reuse scheme the switching of PMOS and NMOS transistors generates negative resistance to compensate the losses of tank circuit. However, this scheme endures the variation in differential output signals in terms of amplitude and phase. This variation in differential output signals is due to the difference of transconductance and parasitic capacitance of the transistors (Yang, & Chiang, (2008)). However, a negative resistance source-degeneration resistor scheme can solve this problem and increase the symmetry of the differential output signals. The schematic of traditional cross-coupled VCO, traditional current-reuse VCO and traditional current-reuse VCO with source degeneration resistance is shown in Figure 5(a–c), respectively.