Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 0

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 1

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 2

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 3

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 4

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 5

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 6

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 7

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 8

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 9

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 10

Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499, US $2,499.00 – Picture 11

Vintage Adjustable Waveform Spark Source Fisher Jarrell Ash John P Walters $2499

US $2,499.00

Bonita Springs, Florida, United States
Jan 29th

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Vintage Adjustable waveform spark source Fisher Jarrell Ash John P Walters $2499 This is a rare Fisher scientific adjustable waveform spark source. This was working when it came out of service. There is a little damage to the green upper housing . The cathode rod was detached as shown. Very easy to solder back.. The green metal was torn a little. MADE BY JARRELL ASH FISHER SCIENTIFIC MODEL # 66-778 ADJUSTABLE WAVEFORM SPARK SOURCE [75[ Inventor: John P. Walters, Madison, Wis. Only the green machine in the photo. Personalized brass dedication plates by the inventor himself. Owned by the university of Wisconsin.... I am also listing the EG&G thyratron driver TM-27 device. A capacitor is charged to a high voltage, and then is discharged through a circuit comprising an analytical spark gap and first and second inductive elements, whereby the discharge current is oscillatory. The waveform of the discharge current is modified by a diode rectifier shunted across the series combination of the analytical spark gap and the second inductive element. To provide for adjustment of the waveform over a wide range, the second inductive element is adjustable in inductance. The first inductive element is also preferably adjustable in inductance. Provision may also be made for changing the capacitance of the capacitor. A reversing switch makes it possible to reverse the polarity of the diode rectifier. One or more control spark gaps may be connected in series with the analytical spark gap. An electronic switching device may be connected across one of the control spark gaps to initiate the discharge of the capacitor. Either or both of the inductive elements may be replaced with other reactances or impedances, such as transmission lines. Coupling may be provided between the inductive elements. Inductance or impedance may be provided in the diode circuit. The capacitor may be replaced with some other source of alternating current or pulses. The spark may be ignited by high voltage, developed at a radio frequency by a quarter wave line. The diode rectifier may be replaced with a silicon controlled rectifier, silicon controlled switch, or some other active element. This invention relates to spark sources, which will find many applications, but are especially advantageous as light sources for spectroscopic analysis, particularly optical emission spectrometry and spectrochemistry. Spark type light sources have an established place in optical emission spectrometry and other spectroscopic analytical techniques, whereby the composition of test samples can be determined. In such techniques, spark discharges are produced across an analytical spark gap. Material from the sample to be analyzed is introduced into the spark gap in that some of the material is vaporized by the spark discharges. The light emitted by the spark discharges is analyzed spectroscopically to determine the composition of the material. Generally speaking, the emitted light produces complex spectra containing many spectral lines. The spectroscopic analysis involves noting the presence of various spectral lines and measuring their relative intensities. By such spectroscopic techniques, it is possible to make accurate analyses of a wide variety of materials. Such techniques are especially valuable in analyzing metals and metal alloys. The basic composition of a metal alloy and the quantities of any impurities present in the alloy can be measured with a high degree of accuracy and sensitivity. Moreover, the test sample of the material to be analyzed can be very small in size. The sparkdischarge is generally produced by charging a capacitor and then discharging it across the analytical spark gap. The capacitor is charged from a direct current power supply which delivers a high voltage. The discharge current through the spark gap tends to be oscillatory because of inductance in the discharge circuit. There is always a certain amount of inherent inductance. Moreover, an inductive element, such as an inductance coil, may be provided in the discharge circuit to provide for an oscillatory discharge at a definite frequency. Thus, the discharge current generally comprises a damped train of alternating current pulses. The damping is provided by the effective resistance of the spark gap and the resistance of the other elements in the discharge circuit. One object of the present invention is to provide a spark type light source which is constructed and arranged so that the waveform of the oscillatory discharge current can be adjusted. Such adjustment makes it possible to carry out the spectroscopic analyses with considerably improved accuracy and facility. By providing for adjustment of the waveform, it is possible to produce a discharge current waveform having a high peak value in one half cycle, followed by a low peak value in the next half cycle. Thus, the current pulses are alternately at high and low peak values. The high value pulses have the advantage of producing high vaporization of the material to be analyzed. The alternate low value pulses make it possible to take spectroscopic photographs having improved contrast and resolution, particularly as to various weak spectral lines filed Feb. 18, which tend to be obscured by background radiation. The accurate determination of intensities of such weak spectral lines is an important factor in the analysis of various materials, particularly as to the presence of impurities in metal alloys. It is a known technique to take spectroscopic photographs which are resolved or spread out as to time, so that the spectral lines corresponding to different portions of the oscillatory discharge current can be separately measured. In accordance with the present invention, a diode rectifier is shunted across the analytical spark gap and a reactive element is connected in series therewith. The reactive element may comprise an inductance coil, a transmission line or some other impedance. Usually, the reactive element predominantly comprises inductive reactance but capacitive reactance and resistance will always be present to some degree. The diode rectifier modifies the waveform of the oscillatory discharge current, so that the pulses are of alternately high and low peak values. The reactive element may be adjustable in inductive reactance. By adjusting this reactance, it is possible to adjust the waveform of the discharge current over a wide range. In particular, the magnitude of the smaller pulses can be changed without greatly affecting the magnitude of the alternate larger pulses. It is even possible to reverse the polarity of theintermediate smaller pulses so that the spark discharge current is undirectional. Preferably, the discharge circuit also includes another reactive element which is not shunted by the diode rectifier, but is the major factor in determining the basic frequency of the oscillatory discharge. The additional reactive element may comprise an inductance coil, a transmission line or some other impedance. Here again, the reactive element usually predominantly comprises inductive reactance, but capactive reactance and resistance will also be present. The additional reactive element may also be adjustable or variable in reactance. The variation of either reactive element affects the waveform of the discharge current. The value of the storage capacitor may also be adjustable. In some cases, the discharge circuit includes one or more control gaps, in series with the analytical spark gap. The discharge of the capacitor may be initiated by triggering an electronic switching device, connected across one of the control spark gaps. Yaba1957 is an asset recovery wholesaler specializing in new and used surplus industrial equipment. We are not a representative of any manufacturer listed; all names, logos, descriptions and other related information are trademarks of their respected companies or manufacturers. All items listed are identified as either new or used and the new may be older surplus. We list all items to the best of our ability and aim to provide the customer with as much information as possible. Yaba1957 is not liable for any products sold, the customer is responsible for proper testing, installation and use of equipment purchased. No warranties are expressed or implied.The sale of this item may be subject to regulation by the U.S. Food and Drug Administration and state and local regulatory agencies. If so, do not bid on this item unless you are an authorized purchaser. If the item is subject to FDA regulation, I will verify your status as an authorized purchaser of this item before shipping of the item. Domestic Shipping . We ship using UPS and FedEx to provide en-route package tracking. International Shipping We ship using UPS, FedEx and USPS. Items shipped by UPS and FedEx are more efficient and provide customers with en-route tracking. Items shipped by USPS cannot be tracked . International buyers are responsible Please research the internet for specifications on this machine. I have the best price around... The sale of this item may be subject to regulation by the U.S. Food and Drug Administration and state and local regulatory agencies. If so, do not bid on this item unless you are an authorized purchaser. If the item is subject to FDA regulation, I will verify your status as an authorized purchaser of this item before shipping of the item."! On Jul-31-12 at 17:20:32 PDT, seller added the following information: SAVE MONEY ON SHIPPING! uShip is the first and largest auction style marketplace for shipping and transportation services. Learn More SHIPPING PRICE ESTIMATOR Delivery ZIP Code: Item Weight: lbs. MORE RESOURCES: uShip Guides and Articles uShip Provider Directory Other Useful Tools & Links