NEW RECTIFIERS

Radio Record, Volume I, Issue 25, 6 January 1928, Page 12

NEW RECTIFIERS

bee eens eerie FOR "A" BATTERY CHARGING Recent invention has produced two. new rectifiers which appear to have many adyautayes over those hitherto in use. A new principle is involved, quite apart from -alve or mechanical rectitication, and not chemical in the usual sense. One of these rectifiers is the "Raytheon A" tube, aud the other the "Kuprox" rectifier, THE RAYTHEON A TUBE. This tube, about the size of one’s thumb, is a ‘‘dry" rectifier in the --nse that paste takes the place of liquid, the container being a steel tube, ‘The advantage of this rectifier is its very low interna) .esistance and consequent. low loss of power, and thus the small ti be is able to pass 23 amps,, and by tsing two tubes in the usual way for doublewave rectification, the maximum .current is increase] to 5 amps. A: stepdown transformer giving & or 9 yuits suffices for half-wave charging, and with this low voltage a good tapering charge is. obtained A safety fuse is included in the circuit. Larger currents than 5 amps may be handled by paralleling the suitable number of tubes. THE "KUPROX" RECTIFIER, This rectifier relies upon the discovery that one-way conductivity exists between a disc of lead and a dise of cupper pressed togethe: with a layer of copper oxide between the two. ‘fue action is probably akin to that between a crystal and cat’s-whisker. A number of pairs ef such discs are holted together to form a rectifier, which, like the one previously mentioned, passes a