Sealed-tube ignitron rectifiers

IN the past decade the advantages of the rectifier, when compared to other forms of conversion equipment, have led to the development of multianode steel tank and glass-bulb rectifiers. The desirable structural features and operating characteristics, however, have not been fully realized when pump-evacuated tanks and fragile glass-bulb rectifiers have been applied to small conversion units of low-voltage rating. Development of a means of starting or igniting¹ a cathode spot, each positive half cycle, on a pool of mercury has stimulated the design of a practicable half-wave or single-anode rectifier. The low density of ionization during the inverse cycle so reduced the shielding necessary to prevent arcback and, in consequence, the arc losses, that these rectifiers could be efficiently applied in the lower-voltage (250 volts d-c) fields.