If an oscillating force is applied to an inverted pendulum it is possible to keep it completely vertical,that is r/2 degrees from the surface the pendulum lies on, with some stability depending on the frequency it osculation at.This paper describes how and why this stability occurs a particular inverted pendulum created by Mr.Janhan Sarashid
HDSL is a powerful, cost-effective, T1-based transport technology that
leverages existing copper infrastructure and is, therefore, of great interest to
both subscribers and service providers. It uses central office (CO) units at the
carrier's office and remote units at the customer site and may, depending
upon distance, require HDSL repeaters over the length of the copper span.
The power needed to operate the repeaters and remote equipment is provided
over the span itself, and must be handled safely for the protection of users
and telephone company craftspersons....
Power Quality Considerations
Harmonics • What Are Harmonics? • Harmonic Sequence • Where Do Harmonics Come From? • Effects of Harmonics on the System Voltage • Notching • Effects of Harmonics on Power System Components • Conductors • Three-Phase Neutral Conductors • Transformers • Effects of Harmonics on System Power Factor • Power Factor Correction Capacitors • IEEE Standard 519
Badrul H. Chowdhury
University of Missouri–Rolla
Tokyo Institute of Technology
Arizona State University
Sputtering is similar to vacuum deposition. In this method, an inert gas such as argon or helium is introduced into a chamber that contains anode and cathode electrodes supplied by an external high-voltage source. The anode contains the sample to be deposited on and the cathode contains the deposited material. The principle is that the high voltage ignites a plasma effect in the inert gas and the gas ions bombard the target containing the material to be deposited. When the kinetic energy of the bombarding ions is sufﬁciently high, some of the atoms from the target surface are freed and...
An Introduction to Microelectromechanical Systems Engineering
The Sandbox: Materials for M E M S
devices are made of n-type and p-type bismuth telluride elements, and are used to cool high-performance microprocessors, laser diodes, and infrared sensors. Peltier devices have proven difficult to implement as micromachined thin film structures.
In this chapter, a brief description of the basic concepts governing the flow of current in a pn junction are discussed. Both intrinsic and extrinsic semiconductors are discussed. The characteristics of depletion and diffusion capacitance are explored through the use of example problems solved with MATLAB. The effect of doping concentration on the breakdown voltage of pn junctions is examined. 10.1 10.1.1 Energy bands INTRINSIC SEMICONDUCTORS
According to the planetary model of an isolated atom, the nucleus that contains protons and neutrons constitutes most of the mass of the atom.
3.1 Theory and Principles Harold Moore 3.2 Power Transformers H. Jin Sim and Scott H. Digby 3.3 Distribution Transformers Dudley L. Galloway 3.4 Underground Distribution Transformers Dan Mulkey 3.5 Dry Type Transformers Paulette A. Payne
3.6 Step-Voltage Regulators Craig A. Colopy 3.7 Reactors Richard Dudley, Antonio Castanheira, and Michael Sharp 3.8 Instrument Transformers Randy Mullikin and Anthony J. Jonnatti 3.9 Transformer Connections Dan D. Perco 3.10 LTC Control and Transformer Paralleling James H. Harlow
3.11 Loading Power Transformers Robert F. Tillman, Jr. 3.
CHAPTER TEN SEMICONDUCTOR PHYSICS In this chapter, a brief description of the basic concepts governing the flow of current in a pn junction are discussed. Both intrinsic and extrinsic semiconductors are discussed. The characteristics of depletion and diffusion capacitance are explored through the use of example problems solved with MATLAB. The effect of doping concentration on the breakdown voltage of pn junctions is examined. 10.1 10.1.
In the latest years much research effort was devoted to envision a new paradigm for
wireless transmission. Results from recent works (Wireless Word Research Forum, 2005)
indicate that a possible solution would lie in utilizing in a more efficient manner the diverse
Radio Access Technologies1
(RATs) that are available nowadays, with the purpose of
enabling interoperability among them and convergence into one global telecom
infrastructure (beyond 3G).
• • • • • • ambient temperature=nhiệt độ xung quanh avalanche effect=hiệu ứng đánh thủng barrier t ti l à b i potential = rào thế breakdown voltage=điện áp đánh thủng conduction band= dãy dẫn depletion layer=miền nghèo (hạt dẫn tự layer miền do) • diode • Doping = pha tạp chất
Từ Vựng (2)
• • • • • • • • forward bias = phân cực thuận free electron = điện tử tự do Hole = lỗ (trống) junction diode = diode tiếp xúc junction t j ti temperature = nhiệt độ tiế xúc t hiệt tiếp ú majori...
Current Flow in an Electrochemical Cell:
Thermodynamic arguments permit the feasibility of overall cell reactions to be predicted, but give no information on rates. To understand the latter it is necessary to consider the effects on various parts of the cell of forcing the cell voltage to assume a value different from that of the equilibrium potential Eeq (V) or electromotive force (emf). In the example of Figure 1, the cell contains hydrochloric acid as aqueous electrolyte and it divides into two compartments by a semipermeable membrane.
A major disadvantage of the lead/acid battery is the decrease in voltage during operation which makes it unsuitable for systems sensitive to voltage fluctuations. Additives like BaSO4 or SrSO4, which are isomorphous to PbSO4, have been used to overcome this problem. Phosphoric acid and the various phosphates have long been used to improve the performance of the positive electrode of the battery. A beneficial effect of phosphoric acid is to inhibit the rate of the self-discharge reaction of the positive electrode in the lead/acid battery. ...
Series and parallel connections are simple to deﬁne in electrical terms, but underlying these basic concepts is a wealth of detail. The battery voltage determines the number of series connections and can have a signiﬁcant effect on battery safety and reliability.
Pompilidotoxins (PMTXs,a and b) are small peptides consisting of 13
amino acids purified from the venom of the solitary waspsAnoplius samari-ensis(a-PMTX) and Batozonellus maculifrons(b-PMTX). They are known
to facilitate synaptic transmission in the lobster neuromuscular junction,
and to slow sodium channel inactivation.
Voltage-gated potassium (KV) channels can form heteromultimeric com-plexes with a variety of accessory subunits, including KCNE proteins. Het-erologous expression studies have demonstrated diverse functional effects
of KCNE subunits on several KV channels, including KCNQ1 (KV7.1)
that, together with KCNE1, generates the slow-delayed rectifier current
(IKs) important for cardiac repolarization.
In this chapter, we review power electronic converters used in ASDs with induction motors. Various types of rectifiers providing the dc supply voltage for inverters feeding the motors are presented, and we describe voltage source inverters, including three-level and soft-switching inverters, and current source inverters. Control methods for inverters, with a stress
on the use of voltage space vectors, are illustrated. Finally, we outline undesirable side effects of the switching operation of power converters.
• A diode is a very useful non-linear device • It allows current to flow in one direction and prevents it flowing in the other
• When a positive voltage is applied across the diode then current will flow • The diode is said to be forward biased • When a negative voltage is applied then the diode is reverse biased and no current will flow
Diode Characteristic Curve
Forward Biased Diode
• A positive voltage is applied to circuit so current will flow • Diode effectively behaves like a short circuit when forward biased...
There is an upward trend that human activities involve more electric power nowadays
and for years to come. And we will soon be facing shortage of electricity supply if we
rely solely on non-renewable power generation from fossil fuels such as coals.
Renewable energy generation has proven effective in meeting the demand.
Microelectromechanical systems (MEMS) have played an increasingly important
role in sensor and actuator applications. And its key contribution is that it has enabled
the integration of multi-components (i.e., electronics, mechanics, fluidics and etc) on a
single chip and their integration has positive effects upon performance, reliability and
cost. Compared to conventional electrostatic, thermal or magnetic actuating schemes,
piezoelectric MEMS inkjet has the advantages of lower power consumption, lower
voltage operation and relatively larger driving force....
Flux and Voltage Induction Machines 6.1 Description 6.2 Concept of Operation 6.3 Torque Development 6.4 Operation of the Induction Machine near Synchronous Speed 6.5 Leakage Inductances and their Effects 6.6 Operating characteristics 6.7 Starting of Induction Motors 6.8 Multiple pole pairs Synchronous Machines and Drives 7.1 Design and Principle of Operation 7.1.1 Wound Rotor Carrying DC 7.1.2 Permanent Magnet Rotor 7.2 Equivalent Circuit 7.3 Operation of the Machine Connected to a Bus of Constant Voltage and Frequency 7.4 Operation from a Source of Variable Frequency and Voltage...