• Country
• United States of America (USA)

• Manufacturer / Brand
• National Company; Cambridge & Malden (MA)

• Year
• 1939

• Category
• Power supply/conditioner or battery or charger 

• Radiomuseum.org ID
• 49546

• • alternative name: National Toy Co.
  • Brand: Thrillbox

Click on the schematic thumbnail to request the schematic as a free document.

• Number of Tubes
• 1

• Valves / Tubes
• 80

• Wave bands
• - without

• Details
• Power Supply (not only Batt.El.)

• Power type and voltage
• Alternating Current supply (AC) / 115 / 230 Volt

• Loudspeaker
• - - No sound reproduction output.

• Material
• Metal case

• from Radiomuseum.org
• Model: Power Supply 697 - National Company; Cambridge &

• Shape
• Miscellaneous shapes - described under notes.

• Dimensions (WHD)
• 190 x 170 x 180 mm / 7.5 x 6.7 x 7.1 inch

• Notes
• The National Power Supply model 697 delivers the following the voltages: filaments 6,3 V AC, B+ 240V DC, 70 mA. The 697 is a typical "doghouse" shaped power supply used to power HRO / HRO-5 series receivers and for instance for the HRO-MX.

• External source of data
• Ernst Erb

• Circuit diagram reference
• Rider's Perpetual, Volume 14 = 1944 = before 1943

• Mentioned in
• Rider's Perpetual, Volume 17 = covering 1947 (Rider's page 17-21)

• Other Models

• Here you find 445 models, 284 with images and 189 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from National Company; Cambridge & Malden (MA)