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Page "Uninterruptible power supply" ¶ 56
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voltage and frequency
In an electrical signal, the voltage, current, or frequency of the signal may be varied to represent the information.
In this, some base signal ( e. g., a sinusoidal carrier wave ) has one of its properties modulated: amplitude modulation involves altering the amplitude of a sinusoidal voltage waveform by the source information, frequency modulation changes the frequency.
For example, diodes are used to regulate voltage ( Zener diodes ), to protect circuits from high voltage surges ( avalanche diodes ), to electronically tune radio and TV receivers ( varactor diodes ), to generate radio frequency oscillations ( tunnel diodes, Gunn diodes, IMPATT diodes ), and to produce light ( light emitting diodes ).
It must be taken into account during experiments, that a conductor carried by a kite can lead to a high voltage toward ground, which can endanger people and equipment, if suitable precautions ( grounding through resistors or a parallel resonant-circuit tuned to transmission frequency ) are not taken.
Using inputs such as input voltage, output voltage, output current, frequency, ambient temperature, and inductance these calculators can predict the losses of the inductors core and AC / DC based on the operating condition of the circuit being used.
The amplitude of the voltage is proportional to the product of the amplitude ( I < sub > P </ sub >) of the current and the frequency ( f ) of the current.
The conductors were energized by a high frequency high voltage power source, producing photographic images typically showing a silhouette of the object surrounded by an aura of light.
The coronal discharges identified as Kirlian auras are the result of stochastic electric ionization processes, and are greatly affected by many factors, including the voltage and frequency of the stimulus, the pressure with which a person or object touches the imaging surface, the local humidity around the object being imaged, how well grounded the person or object is, and other local factors affecting the conductivity of the person or object being imaged.
A DC-blocking capacitor may be inserted in series with the input resistor when a frequency response down to DC is not needed and any DC voltage on the input is unwanted.
Increase in intensity of incident beam ( keeping the frequency fixed ) increases the magnitude of the photoelectric current, though stopping voltage remains the same.
* Electrical voltage and frequency
If the flux in the core is purely sinusoidal, the relationship for either winding between its rms voltage E < sub > rms </ sub > of the winding, and the supply frequency f, number of turns N, core cross-sectional area a and peak magnetic flux density B is given by the universal EMF equation:
Operation of a transformer at its designed voltage but at a higher frequency than intended will lead to reduced magnetizing current.
A lower frequency reduces the effect of the inductance in the transformer, so the voltage needed to induce the current can be reduced.
Digital systems refer to the ' knee frequency ', the amount of time the digital voltage to rise from 10 % of a nominal digital ' 0 ' to a nominal digital ' 1 ' or vice-verse.
This has given rise to techniques such as dynamic voltage and frequency scaling ( DVFS ) to minimize overall power.
This table contains specifications for certain SPARC processors: frequency ( megahertz ), architecture version, release year, number of threads ( threads per core multiplied by the number of cores ), fabrication process ( micrometers ), number of transistors ( millions ), die size ( square millimetres ), number of I / O pins, dissipated power ( watts ), voltage, and cache sizes — data, instruction, L2 and L3 ( kibibytes ).
The voltage, power, frequency, load factor, and reliability capabilities of the transmission system are designed to provide cost effective performance for the customers.
To load balance the voltage and frequency can be used as a signaling mechanism.
This procedure is done using small electrodes ( about 1mm in diameter ), placed either inside or surrounding the target tissue to apply short, repetitive bursts of electricity at a predetermined voltage and frequency.
It has the advantage of being tied in frequency and amplitude to the relatively stable digital clock signal and power ( voltage ) supply, respectively, that are used by the digital channel bank.
This converts data between the digital signals used by computers and the voltage signal of a suitable frequency range which is then applied to the phone line.

voltage and power
`` By the way '', said Mr. Blatz, packing his tools into a battered carrier, `` them power tools needs extra voltage.
The current drawn by typical constant-voltage energy distribution systems is usually dictated by the power ( watts ) consumed by the system and the operating voltage.
so it follows that if the voltage is doubled and the power remains the same, the current will be halved .</ ref >
RF amplifiers are often specified in terms of the maximum power gain obtainable, while the voltage gain of audio amplifiers and instrumentation amplifiers will be more often specified ( since the amplifier's input impedance will often be much higher than the source impedance, and the load impedance higher than the amplifier's output impedance ).
For example, an audio amplifier with a gain given as 20 dB will have a voltage gain of ten ( but a power gain of 100 would only occur in the event the input and output impedances were identical ).
Small could mean less than 3 dB below ( i. e., power output < 1 / 2 or voltage output < 0. 707 of ) the maximum value, or more rarely 10 dB below, or it could mean below a certain absolute value.
This often matches conventional current direction, because in many circuits the power supply voltage is positive with respect to ground.
A is a low voltage power supply to heat cathode C ( a " cold cathode " was used by Crookes ).
B is a high voltage power supply to energize the anode P. Shadow mask M is connected to the cathode potential and its image is seen on the phosphor as a non-glowing area.
Before the development of silicon power rectifier diodes, cuprous oxide and later selenium was used ; its low efficiency gave it a much higher forward voltage drop ( typically 1. 4 to 1. 7 V per " cell ", with multiple cells stacked to increase the peak inverse voltage rating in high voltage rectifiers ), and required a large heat sink ( often an extension of the diode ’ s metal substrate ), much larger than a silicon diode of the same current ratings would require.
These include transformers, electric generators, electric motors, high voltage engineering and power electronics.
Central power stations became economically practical with the development of alternating current power transmission, using power transformers to transmit power at high voltage and with low loss.
The invention in the late nineteenth century of the transformer meant that electrical power could be transmitted more efficiently at a higher voltage but lower current.
Dependent Sources depend upon a particular element of the circuit for delivering the power or voltage or current depending upon the type of source it is.
** In power engineering, a " bus " is any graph node of the single-line diagram at which voltage, current, power flow, or other quantities are to be evaluated.
The gain may be specified as the ratio of output voltage to input voltage ( voltage gain ), output power to input power ( power gain ), or some combination of current, voltage and power.

voltage and produced
For example, in sound recording, fluctuations in air pressure ( that is to say, sound ) strike the diaphragm of a microphone which induces corresponding fluctuations in the current produced by a coil in an electromagnetic microphone, or the voltage produced by a condensor microphone.
Many automotive Hall effect sensors have a built-in internal NPN transistor with an open collector and grounded emitter, meaning that rather than a voltage being produced at the Hall sensor signal output wire, the transistor is turned on providing a circuit to ground through the signal output wire.
The principle behind cold cathode version is the same, except that electrons are produced in the discharge of a high voltage.
Early analog synthesizers were usually monophonic ( capable of playing only one note at a time ), and controlled via a voltage produced by their keyboards.
* Coil protection – suppress the surge voltage produced when switching the coil current
The conductivity is varied by the electric field that is produced when a voltage is applied between the gate and source terminals ; hence the current flowing between the drain and source is controlled by the voltage applied between the gate and source.
The voltage produced is dependent on, but not necessarily proportional to, the difference of temperature of the junction to other parts of those conductors.
At the power stations the energy is produced at a relatively low voltage between about 2. 3 kV and 30 kV, depending on the size of the unit.
The alternating current signal produced by the flow of this charge is amplified and used as an analogue for the DC voltage applied to the capacitor.
* If the high and low signal levels have the same voltage with opposite polarity, coded signals have zero average DC voltage, thus reducing the necessary transmitting power and minimizing the amount of electromagnetic noise produced by the transmission line.
Electromagnetic noise is produced in the source due to rapid current and voltage changes, and spread via the coupling mechanisms described earlier.
Some forms of DC ( such as that produced by a voltage regulator ) have almost no variations in voltage, but may still have variations in output power and current.
If otherwise, it indicates that the voltage isn't increasing linearly, and therefore that the magnetic field produced by the deflection yoke is not linear.
It has been proposed therefore to heat such materials simultaneously throughout their mass by means of the dielectric loss produced in them when they are subjected to a high voltage, high frequency field.
Depending upon the type of end-use, this type of DC current may then be further modified into the type of relatively constant voltage DC characteristically produced by such sources as batteries and solar cells.
Alternatively ( and some would say properly, in the context of electrocardiography ), the word lead may refer to the tracing of the voltage difference between two of the electrodes and is what is actually produced by the ECG recorder.
Inter-operation with RS-232 devices may be impossible as the serial port cannot withstand the voltage levels produced and may have other differences that " lock in " the user to products of a particular manufacturer.
It produced a small DC voltage.
The voltage produced is proportional to the temperature difference between the two junctions.
The voltage difference, V, produced across the terminals of an open circuit made from a pair of dissimilar metals, A and B, whose two junctions are held at different temperatures, is directly proportional to the difference between the hot and cold junction temperatures, T < sub > h </ sub > − T < sub > c </ sub >.

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