Patent GB-242270-A (GB)
Title: Improvement in containers for electrical appliances
IPC: H05K5/04
Filed: 1925-10-24
Abstract: 242,270. Dubilier Condenser Co. (1925), Ltd., (Assignees of Forbes, E. D.). Oct. 28, 1924, [Convention date]. Thermionic valve circuits. - A number of electrical appliances designed to take current from a supply circuit and so modify the current as to render it suitable for use under conditions prevailing in the load circuit, which may be the anode or plate circuits of a radio receiving set, are housed as a compact unit in a container, the partitions of which serve to shield the parts one from another. In the arrangement shown in Fig. 5, alternating current supplied to the input terminals 18<a>, 18<b> is converted by the rectifying device 10 into a unidirectional pulsating current which is passed through a smoothing-out circuit and delivered to the output terminals 24. The several devices constituting this arrangement are, according to the invention, housed as a compact unit in a metal &c. casing 1, Fig. 1, which is divided by partitions 2, 5, 7 into compartments 4, 6, 3, 8. The lamp 10 is detachably mounted in a socket 11 in the compartment 4, which is provided with a hinged lid 16. The front wall of the compartment 4 carries (1) an apertured insulator 17 through which the cord containing the input conductors is passed, (2) the adjustable resistance 19 with its operating shaft 20 and knob 21, and (3) the switch 22. The transformers 12, made up in a single bundle, are positioned in the compartment 6, whilst the small compartment 8 houses the pair of condensers 13. The compartment 3 accommodates a stack 9 made up of the choke coils 9<a>, condensers 9<b> and fixed resistance 9R, the stack having a recess 26 at the top to receive an adjustable resistance 25 which is connected between two of the terminals 24 and is operated by a shaft 27 and knob 28. The terminals 24 are carried by an insulating panel 23 which covers a large opening in the output end of the casing, one of the terminals being electrically connected by a metal strip to the casing. Fig. 11 illustrates a circuit arrangement for modifying direct current supplied to the terminals 18a, 18b and which differs from that shown in Fig. 5 in that the rectifier 10, transformers 12 and resistance 19 are omitted, and a small condenser 41 is bridged between two of the terminals 24<a>, which, in this case, number five. An impedance r in multiple with one of the coils 9<a> may be provided to improve the smoothing out and prevent oscillations at the natural frequency of the circuit. The casing 31, Fig. 6, for housing this arrangement is mounted on a detachable base 32 and is divided into three compartments 36, 33, 37 by a U-shaped plate 38 and side plates 39, Fig. 10. A stack 40, comprising the choke coils 9<a> and all the condensers 13 and 9<b>, is accommodated in the middle compartment 33. The insulator 17 and switch 22 are mounted in the front wall and the, panel 23 with the terminals 24<a> and the adjustable resistance 25 are mounted in the back wall of the casing as previously described with reference to Fig. 1. The small condenser 41 is mounted in the rear compartment 37 below the resistance 25.