Master equation for operational amplifiers: stability of negative differential converters, crossover frequency and pass-bandwidth

Mishonov, Todor M.; Danchev, Victor I.; Petkov, E. G.; Gourev, Vassil N.; Dimitrova, Iglika M.; Serafimov, N. S.; Stefanov, A. A.; Varonov, Albert M.

doi:10.1088/2399-6528/ab050b

Cited by 9 publications

(5 citation statements)

References 17 publications

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“…where s ≡ jω is a widely used notation in electronics, α 0 ≡ 1/G 0 and the time constant τ = 1/ω c ≡ 1/2π f c is a convenient parametrization of the crossover frequency [7][8][9] and Ref. The schematics of the GIC analyzed in the present paper is shown in Fig.…”

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confidence: 99%

Tunable high-Q resonator by general impedance converter

Mifune

Mishonov

Serafimov

et al. 2021

Review of Scientific Instruments

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A tunable high-Q resonator is performed in the schematics of the General Impedance Converter (GIC). In the framework of frequency dependent open-loop gain of operational amplifiers, a general formula of the frequency dependence of the impedance of GIC is derived. The explicit formulas for the resonance frequency and Q-factor include as an immanent parameter the crossover frequency of the operational amplifier. Voltage measurements of GIC with a lock-in amplifier perfectly agree with the derived formulas.

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confidence: 99%

Tunable high-Q resonator by general impedance converter

Mifune

Mishonov

Serafimov

et al. 2021

Review of Scientific Instruments

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“…in kHz to MHz range which is just our case. Further we use the basic equation of Op amps in the form [41,42,43],…”

Section: Discussionmentioning

confidence: 99%

Set-up for observation thermal voltage noise and determination of absolute temperature and Boltzmann constant

Mishonov¹,

Serafimov²,

Petkov³

et al. 2022

Eur. J. Phys.

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We describe a set-up for measurement of the absolute zero by Johnson–Nyquist thermal noise which can be performed within a week in every high-school or university. Necessary electronic components and technical guidelines for the construction of this noise thermometer are given. The operating temperature used is in the tea cup range from ice to boiling water and in this sense the set-up can be given in the hands of every high school and university physics student. The measurement requires a standard multi-meter with thermocouple and voltage probe and gives excellent for education purposes percent accuracy. The explanation is oriented to university level but due to the simplicity of the explanation motivated high-school students can follow the explanation derivation of the used formulas for determination of the absolute zero and the Boltzmann constant. As a by-product our set-up gives a new method for the determination of the spectral density of the voltage e N and current noise i N of operational amplifiers.

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“…The electrical impedance (Z) is from Ohm's law according to Eq. 2 [24], where there are voltage (U) and current (I). Z = U / I.…”

Section: Fig 4 Specimens With Electrodes Of Each MIX Proportionmentioning

confidence: 99%

Analysis of the Electrical and Mechanical Properties of Cement Composite Produced with Brake Lining Waste

Palma e Silva,

Lintz,

Gachet

2024

Mechanics, Materials and Manufacturing (10th ICMMM)

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Cement composites such as mortars and concretes with electrically conductive properties, have different uses, such as electromagnetic shielding, electrical grounding, cathodic protection, vehicle traffic monitoring, and the detection of strains and cracks in buildings. However, for these composites to have their electrical conductivity increased, it is necessary to incorporate electrically conductive materials, such as metals and carbon. Nonetheless, such materials tend to be expensive, which makes the manufacture of the composite more expensive. In this sense, using waste materials can help reduce costs and minimize impacts on the environment. Therefore, cement mortars were produced in this research with waste of brake linings from heavy vehicles, which may contain metallic and carbon-based materials. The mortars produced had part of the sand replaced by up to 70% crushed waste, which was submitted for analysis of compressive strength and electrical impedance. Preliminary results showed a decrease in the impedance (showing a trend of increasing electrical conductivity) of mortars with brake lining waste compared to mortars without waste, as well as a decrease in compressive strength. Finally, the use of brake lining waste in the production of cement composites can help reduce the consumption of natural resources as well as minimize the disposal of waste in landfills, which in both cases contributes to the sustainability of the environment.

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Master equation for operational amplifiers: stability of negative differential converters, crossover frequency and pass-bandwidth

Cited by 9 publications

References 17 publications

Tunable high-Q resonator by general impedance converter

Tunable high-Q resonator by general impedance converter

Set-up for observation thermal voltage noise and determination of absolute temperature and Boltzmann constant

Analysis of the Electrical and Mechanical Properties of Cement Composite Produced with Brake Lining Waste

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