Cathode ray oscilloscopes

Oscillograph. A cathode-ray oscilloscope in which a photographic or other permanent record is produced by the electron beam of a cathode-ray tube. A cathode-ray oscilloscope is a test instrument that uses a cathode-ray tube to make visible on a fluorescent screen the instantaneous values and waveforms of electrical quantities that are rapidly varying as a function of time... 

In transient measurements one must record rapidfy changing currents or potentials. In the past, cathode-ray oscilloscopes have been used for this purpose (at present, improved recording devices or computers are used as well), hence the term oscillographic polarography (or oscillographic voltammetry). This term is unfortunate since it reflects only the device used to record the results, rather than the essential features of the method used for the measurements. 

Inputs and outputs for function generator and cathodic-ray oscilloscope (or rapid x y recorder) in single sweep and cyclic VA... 

This method is similar to continuous flow method except that the rate of flow is continuously varied and the analysis is made at a fixed point along the observation tube. Since the rate of flow changes with time, the reaction mixtures arriving at observation point have different time. In the accelerated flow method the output from a photo electric colorimeter is fed to a cathode-ray oscilloscope, which sweeps out a complete time-concentration record which may be photographed. The method is useful for very rapid enzyme reactions and requires only small quantities of reactants. 

Fig. 11. Modification18 of Sofica photometer for use at 0 = 1060 nm pd - monitoring photodiode, bs — beam splitter, i - iris, pm — photomultiplier, ire — infrared converter, ps - power supplies, cro - cathode ray oscilloscope, a - aperture, p — reflecting prism, c — cell...

In order to conveniently detect and display the resonance signal, audio modulation coils are used to modulate the static magnetic field. Close to a resonance the rf voltage will be audio amplitude modulated in the same way that a carrier wave is audio amplitude modulated in radio broadcasting. In this way by modulating with an amplitude large compared to the line width, the entire resonance signal may be displayed on a cathode-ray oscilloscope. 

This is the transient method for which most experience is available. It was introduced by Bowden and Rideal (1928). The name comes from that of Galvani4 and means, in fact, current. Thus, Galvanostatic transient means short-term constant current. The circuitry is simple. It consists of nothing more than a measurement cell in series with an adjustable resistance much larger in value than the resistance of the cell, a power source, a rapid action switch, and a cathode ray oscilloscope to record the variation in the potential of the working electrode with time. A typical potentialtime relation is shown in Fig. 8.6. 

In the linear sweep technique, a recording of the current during the potential sweep (say, from 0.0 V on the normal hydrogen scale to 1.2 V positive to it in a 1 M H2 S04 solution) completes one act of the basic experiment. However, and hence the title of this part of the chapter, the electronics can be programmed so that when the electrode potential reaches 1.20 V, it begins a return sweep, going from 1.2 to 0.00 V, NHS. Completion of the two sweeps and back to the starting point is one act in what is called cyclic voltammetry.16 The current is displayed on a cathode ray oscilloscope screen on an X Y recorder, and it is normal to cany out not one but several and often many cycles. Much information is sometimes contained in the difference between the second and other sweeps in comparison with the first (Fig. 8.10). 

S. D.Uslan, "Encyclopedia on Cathode-Ray Oscilloscopes and Their Uses , Rider Publisher, Inc, NY(1950) 18)W.D.Chesterman, "Photographic Study of Rapid Events ,... 

The pulses produced by this action proceed thru mixer circuits to an oscillograph where they are displayed on a cathode-ray oscilloscope screen along with time calibration markers. This display is photographed and detonation rates are computed from expl increment lengths, and measurements of time displacements are read on a film reader... 

The next question is How do we write it We have no standard technique to do this now. But let me argue that it is not as difficult as it first appears to be. We can reverse the lenses of the electron microscope in order to demagnify as well as magnify. A source of ions, sent through the microscope lenses in reverse, could be focused to a very small spot. We could write with that spot like we write in a TV cathode ray oscilloscope, by going across in lines, and having an adjustment which determines the amount of material which is going to be deposited as we scan in lines. 

Sustained contraction of muscle fibers produces repetitive electrical potentials in them that increase in rapidity with strength of contraction and in number as more motor units take part. These potentials may be conducted from a coaxial needle electrode in the muscle, amplified, and their amplitude and frequency analyzed and recorded on a cathode-ray oscilloscope as the very typical full interference pattern of normal voluntary contraction. Characteristic departures from this normal electro-myogram are of very great importance in the diagnosis of muscle disease (B21a). 

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