Patent GB-244738-A (GB)
Title: Improvements in or relating to oscillographs
IPC: G01R13/32
Filed: 1925-11-24
Abstract: 244,738. Siemens - Schuckertwerke Ges. Dec. 20, 1924, [Convention date]. Oscillographs for recording migratory wave phenomena, with a slow advance and quick return of the spot of light, are provided with means by which the variable phenomena and the advance or return of the spot are released by the same cause. Fig. 1 shows an arrangement of apparatus in which migratory waves are set up by closing a switch 3 connecting a direct or alternating current generator 2 to a circuit, and are applied to a pair of plates 26 of a cathode-ray oscillograph 4. Alternatively, the migratory waves may be started by tho discharge of a condenser charged from a direct-current source. The slow advance and quick return of the spot of light is effected by means of a second pair of plates 5, at right-angles to the first pair, connected across a condenser 6, which is gradually charged through a resistance 9 from a direct-current source 8 and quickly discharged through a spark gap 9 in series with a resistance 10. The discharge current operates a relay 11 which closes the switch 3, thereby effecting the simultaneous starting of the wave to be recorded and the changing of the condenser 6. An adjustable tension 12 may be provided for adjusting the zero line. This adjustment may alternatively be effected by coupling the plates 5 to the condenser 6 through a transformer which cancels the direct tension components of the condenser, or a capacity such as an electrostatic tension divider may be employed. The release of the migratory waves may be effected from the condenser 6 through a relay operating at any desired value of the condenser tension or current. Conversely the charging or discharging of the condenser may be controlled by the variable phenomenon to be examined, which is repeated and automatically released by an automatic switch or otherwise. For recording variable phenomena of very short duration, the frequency of the switching sequence is made very great by employing ion or electron switches. One such construction is shown in Fig. 3, in which the discharge of the condenser 6 across the spark gap 9 causes, through a transformer 14, a spark to traverse the gap 15. A further construction is shown in Fig. 4, in which the connection of the conductor 1 to the generator 2 is effected by means of two mercury vapour tubes 16, 17, the tube 17 being connected through a condenser 18 in parallel with the tube 16. The ignition of the tubes 16, 17 is effected by the discharge of the condenser 6 through a mercury vapour tube 9 in series with the primary winding of a transformer 19. The tube 17, owing to insufficient tension, is switched out when the tube 16 allows any current to pass, the condenser 18 then being charged. When the tube 17 receives ignition tension from the transformer 19, it is temporarily switched in. The conductor 21 is arranged to retard the impulse, as by inserting choking-coils, so that the ignition impulse from the transformer 19 reaches the tube 16 later than the tube 17. During the charging of the condenser 6, the tube 16 is switched in. When discharge occurs across the tube 9, the tube 17 is ignited. The charge of the condenser 18 then sends a current through the tube 16 in the reverse direction to that already flowing. The tube 16 is first switched out, and is immediately afterwards switched in bv the ignition current arriving over the conductor 21, releasing migratory waves on to the condenser 1 at the instant when charging of the condenser 6 has started. In a further modification shown in Fig. 5, the discharge of the condenser 6 is controlled by the waves to be examined. The generator 2 is connected to the conductor 1 through a spark gap 22 so dimensioned that it is operated once for each half-wave of an alternating current. Operation of the spark gap 22 causes, through a transformer 23, ignition of a mercury vapour tube 24 which discharges the condenser 6.