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Topic: Hartley oscillator


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In the News (Sat 15 Jun 19)

  
  www.oscillatorguide.com - Hartley Oscillator
The Hartley oscillator is an LC electronic oscillator that derives its feedback from a tapped coil in parallel with a capacitor (the tank circuit).
The two versions of this oscillator are the series-fed and the shunt-fed. The main difference between the Armstrong and the Hartley oscillators lies in the design of the feedback (tickler) coil.
Hartley oscillator are inductively coupled, variable frequency oscillators where the oscillator may be series or shunt fed. Hartley oscillators have the advantage of having one centre tapped inductor and one tuning capacitor.
www.oscillatorguide.com /hartley-oscillator.html   (266 words)

  
  Hartley oscillator - Wikipedia, the free encyclopedia
The Hartley oscillator is an LC electronic oscillator that derives its feedback from a tapped coil in parallel with a capacitor (the tank circuit).
A Hartley oscillator is essentially any configuration that uses a pair of series-connected coils and a single capacitor (see Colpitts oscillator for the equivalent oscillator using two capacitors and one coil).
The Hartley oscillator was extensively used on all broadcast bands including the FM 88-108MHz band.
www.sciencedaily.com /encyclopedia/hartley_oscillator   (234 words)

  
 Ralph Hartley
He invented the Hartley oscillator[?] and contributed to the foundations of information theory.
Hartley was born in Spruce, Nevada[?] and attended the University of Utah, receiving an A.B. degree in 1909.
A patent for the oscillator was filed on June 1, 1915 and awarded on October 26, 1920.
www.ebroadcast.com.au /lookup/encyclopedia/ra/Ralph_Hartley.html   (329 words)

  
 Hartley
It is likely that Hartley was aware of the earlier work of Nyquist and that he assumed implicitly, as Nyquist did explicitly, that all symbol sequences were of the same length or size.
Hartley was aware of a relationship between the amount of energy in an information system and the amount of information that could be transmitted.
One drawback of using the Hartley transform is that it is difficult to extend to higher dimensions because it is not a separable transform.
www.geocities.com /neveyaakov/electro_science/hartley.html   (878 words)

  
 Hartley oscillator   (Site not responding. Last check: )
The Hartley oscillator is an L C oscillator that derives its feedback from a tapped coil and is varied in frequency by a variable capacitor.
A Hartley oscillator is therefore a type of inductively coupled variable frequency oscillator.
Hartley oscillators may be series or shunt fed. Structure : : One centre tapped inductor.
www.serebella.com /encyclopedia/article-Hartley_oscillator.html   (198 words)

  
 Included Footer for Requirements Discussion   (Site not responding. Last check: )
An oscillator is a device for producing ac power, the output frequency of which is determined by the characteristics of the device.
There are some requirements for the harmonic oscillation, that there should be an active element producing amplification, a positive feedback should lead to negative resistance, a frequency selective network which mainly determines the oscillation frequency and a nonlinearity, which is called limiting to maintain the oscillation amplitude in stable equilibrium.
Hartley oscillators are inductively coupled; variable frequency oscillators where the oscillator may be series or shunt fed. Hartley oscillators have the advantage of having one centre tapped inductor and one tuning capacitor.
www.ee.ryerson.ca /~akhan/Theory.htm   (1225 words)

  
 Electronics 16
The simplest crystal oscillator is the Pierce oscillator, shown in the figure on the left.
The amplitude of oscillation at the drain was 24 V with R = 1k, the RF voltage across the choke reversing in direction during the cycle.
Other oscillators are discussed on other pages, for example The VTVM and GDO, where the grid-dip oscillator is studied, and Vacuum Tubes, where local oscillators for superheterodynes are presented.
mysite.du.edu /~etuttle/electron/elect16.htm   (2560 words)

  
 www.oscillatorguide.com - Oscillator   (Site not responding. Last check: )
Oscillators are devices that are used to generate repetitive signals.
Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum.
For example, a quartz watch uses a quartz oscillator to keep track of what time it is. An AM radio transmitter uses an oscillator to create the carrier wave for the station, and an AM radio receiver uses a special form of oscillator called a resonator to tune in a station.
www.oscillatorguide.com   (425 words)

  
 OTB - Rotten Signals: How To Cure Them
If we plot a curve of oscillator frequency against changes in plate voltage it will be found that as the voltage is increased from zero there will be a continuous frequency change until the final voltage is reached.
The excitation is increased in the Hartley circuit by moving the filament tap nearer the plate end; in the t.p.t.g.
As soon as the oscillator is coupled to an antenna or feeder system and power is taken out, the antenna or feeders become a part of the tuned circuit.
www.antiquewireless.org /otb/rotten.htm   (3085 words)

  
 www.oscillatorguide.com - Mcclellan Oscillator
When the oscillator reaches –100 the opposite is true and traders should be alert to a rally.
Typically, the McClellan Oscillator is juxtaposed against the New York Stock Exchange Index (NYSE), as that is considered the broadest measure of trading on that exchange.
McClellan Oscillators can be calculated on any exchange, and the Oscillator for the Nasdaq also is vital for diagnosing when that exchange is at an extreme.
www.oscillatorguide.com /mcclellan-oscillator.html   (435 words)

  
 Electronics 16
The amplitude of oscillation at the drain was 24 V with R = 1k, the RF voltage across the choke reversing in direction during the cycle.
In the Hartley circuit, the inductor is tapped to match the low impedance of the collector circuit (or plate, for a tube), while the other end supplies the base (or grid).
Other oscillators are discussed on other pages, for example The VTVM and GDO, where the grid-dip oscillator is studied, and Vacuum Tubes, where local oscillators for superheterodynes are presented.
www.du.edu /~etuttle/electron/elect16.htm   (2560 words)

  
 Tracking Advances In VCO Technology - Maxim/Dallas
Hartley made use of improvements in vacuum-tube technology and devised a oscillator circuit in which the vacuum tube acted as an amplifying device with inductive feedback applied to create a regenerative oscillation.
The frequency of oscillation was established by the coil inductance and the circuit capacitance.
The Hartley oscillator circuit was popular in transmitters and was quickly adapted for use in World War I. Both transmitters and receivers made use of the new tube-based oscillators circuit.
www.maxim-ic.com /appnotes.cfm/appnote_number/1768   (3023 words)

  
 R.V.L. Hartley: The Transmission of Information, first edition, first printing
R.V.L. Hartley, a research engineer at Bell Labs and the inventor of the Hartley oscillator, was one of the first to make progress in quantitatively measuring the capacities of various types of information systems to transmit information.
In his paper, Hartley had arrived at many of the most important ideas of the mathematical theory of communication: the difference between information and meaning, information as a physical quantity, the logarithmic rule for transmission of information, and the essential concept of noise as an impediment in the transmission of information
Although Hartley, in 1928, was primarily concerned with information transmission in the telephone, telegraph, and television, his work, of course, later became of great importance in the development of the computer.
www.manhattanrarebooks-science.com /hartley.htm   (354 words)

  
 LC Oscillators
This oscillator is very much like a RF amplifier, but a new coil, called the tickler coil, is connected between the plate and the B+, or high voltage supply.
The difference between the Armstrong oscillator and the Hartley oscillator is that the tickler coil is part of the LC circuit.
The Colpitts oscillator is very similar to the Hartley oscillator, but instead of a tapped grid coil, it has tapped capacitance.
www.electronixandmore.com /articles/oscillators.html   (1219 words)

  
 Parts for Ham Radio
Oscillators may be classified by name, such as Armstrong, Hartley, Colpitts, or by the manner in which dc power is applied.
It is generally used as a local oscillator in receivers, as a source in signal generators, and as a radio-frequency oscillator in the medium- and high-frequency range.
The identifying characteristics of the Armstrong oscillator are that (1) it uses an LC tuned circuit to establish the frequency of oscillation, (2) feedback is accomplished by mutual inductive coupling between the tickler coil and the LC tuned circuit, and (3) it uses a class C amplifier with self-bias.
www.earth2.net /parts/?course/90902004/question   (3005 words)

  
 Automatically stabilized oscillator - Patent 4112393
In the absence of oscillations the base is biased for class A operation and the resulting feed-back current charges the bias circuit to shift the operating point to class C operation.
These circuits must include means for stabilizing the oscillator against changes in the inductance of the tank circuit resulting from changes in the coupling of the load to the inductance or from variations in impedance of the load which result in reflected variations in impedance of the tank circuit.
The present invention is broadly directed toward an oscillator for generating induction heating currents employing a bias network controlled by the regenerative feed-back which shifts the operating point of a transistor to adjust the conduction period to maintain stable oscillation independent of variations in the load impedance.
www.freepatentsonline.com /4112393.html   (2221 words)

  
 oscillators
Colpitts oscillators are somewhat similar to the shunt fed Hartley circuit except the Colpitts oscillator, instead of having a tapped inductor, utilises two series capacitors in its LC circuit.
Hartley oscillator are inductively coupled, variable frequency oscillators where the oscillator may be series or shunt fed. Hartley oscillators have the advantage of having one centre tapped inductor and one tuning capacitor.
The voltage controlled oscillator is tuned across its band by a "clean" dc voltage applied to the varactor diode to vary the net capacitance applied to the tuned circuit.
www.electronics-tutorials.com /oscillators/oscillators.htm   (702 words)

  
 Oscillator types, Wien Bridge oscillators, Colpitts Oscillator, Hartley Oscillator, Blocking oscillator, RC Oscillator, ...
Clapp oscillator Clapp oscillator, The Clapp oscillator is one of several types of electronic oscillator constructed from a transistor (or vacuum tube) and a positive feedback network,...
Colpitts oscillators Colpitts oscillators are somewhat similar to the shunt fed Hartley circuit except the Colpitts oscillator, instead of having a tapped inductor, utilises two series capacitors in its LC circuit
Hartley oscillator The Hartley oscillator is an LC electronic oscillator that derives its feedback from a tapped coil in parallel with a capacitor (the tank circuit).
www.educypedia.be /electronics/analogosciltypes.htm   (584 words)

  
 Hartley Oscillator Electronic Circuits
Electronic Canary: This circuit is a modified hartley oscillator with a couple of extra components included.
This causes the oscillation to stop, the capacitor discharges through the base emitter circuit of the transistor and oscillations start again.
Sine Wave Oscillators: This oscillator gives a really beautiful sine wave, and is an excellent choice for a precision audio oscillator.
www.discovercircuits.com /O/o-hartley.htm   (706 words)

  
 Class E Transmitters - Two band VFO (80 and 160 meters)
Referring to the VFO Schematic, the circuit uses a Hartley oscillator operating between approximately 7 to 8 mHz.
The buffered oscillator output is then divided by 2 for 75 meter operation or divided by 4 for 160 meter operation.
On 75 meters, the oscillator output is divided one time (by 2), and on 160 meters the oscillator output is divided by 4.
www.classeradio.com /vfo.htm   (915 words)

  
 HARTLEY OSCILLATOR
The two versions of this oscillator are the series-fed and the shunt-fed. The main
Instead, in the Hartley oscillator, the coil in the tank circuit is a split
One version of a SERIES-FED HARTLEY OSCILLATOR is shown in figure 2-13.
www.tpub.com /content/neets/14181/css/14181_81.htm   (246 words)

  
 oscillators
Some people regard the design of RF Oscillators to be something akin to a "fl art" and after many years of swearing at "cranky" oscillators I'm not all too sure they are all that wrong.
Ultimately a state of equilibrium is reached where the losses in the circuit are made good by consuming power from the power supply and the frequency of oscillation is determined by the external components, be they inductors and capacitors (L.C.) or a crystal.
Frequency or phase stability of an oscillator is customarily considered in the long term stability case where frequency changes are measured over minutes, hours, days even years.
my.integritynet.com.au /purdic/oscillators.htm   (2263 words)

  
 Hartley oscillator - Education - Information - Educational Resources - Encyclopedia - Music
The Hartley oscillator is an LC electronic oscillator that derives its feedback from a tapped coil and is varied in frequency by a variable capacitor.
A Hartley oscillator is therefore a type of inductively coupled variable frequency oscillator.
Hartley oscillators may be series or shunt fed.
www.music.us /education/H/Hartley-oscillator.htm   (323 words)

  
 Voltage controlled oscillator - Patent 6075421
A voltage controlled oscillator as claimed in claim 1, wherein in use said voltage controllable variable resonant circuit provides for variations in frequency at said controllable variable frequency output in response to variations in direct current voltages applied at said control input.
One problem with this oscillator is that it requires a relatively small value of capacitance in the resonant circuit which is therefore a limitation on bandwidth.
Hartley wideband voltage controlled oscillators are often used to obtain a wider bandwidth coverage than is achievable by Colpitts voltage controlled oscillators.
www.freepatentsonline.com /6075421.html   (2434 words)

  
 Theory of Operation   (Site not responding. Last check: )
The RF signal, after passing through the input filter, is connected to the input of the double balanced mixer, pins 1 and 2.
A panel mounted variable capacitor is used to change the frequency of the VFO to a frequency in the desired range.
The oscillator, connected to pins 6 & 7, is changed in frequency with inductance and capacitance plus or minus 500-1500 hz.
www.pan-tex.net /usr/r/receivers/ra01011a.htm   (570 words)

  
 The HARTLEY Surname Hall of Fame 2 M-R
Marcellus HARTLEY DODGE was a descendant of Marcellus HARTLEY.
Marie Hartley made sure that the Yorkshire Dales would be long remembered through 33 books, thousands of paintings and photographs and an extraordinary collection of everything from oatcake pans to knitting sticks.
Hartley's first solo exhibition at 291 in 1909, led to his long-standing affiliation with the Stieglitz circle of artists, writers, and cultural critics.
www.hartleyfamily.org.uk /Fame2MR.htm   (1298 words)

  
 [No title]
As oscillations develop, grid bias is produced and the gain of the tube decreases to some steady value appropriate to sustain oscillations.
In a Hartley oscillator, the feedback is through the mutual inductance of the coil(s).
With a tube oscillator with grid-leak bias, the oscillations increase until the developed bias voltage reduces the gain of the tube to just that needed to keep the oscillations constant.
www.ibiblio.org /pub/academic/agriculture/agronomy/ham/GLOWBUGS/ATL/Vol01_150_to_199/v01_n160.glo.html   (1939 words)

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