Tube-number record
VTP 6991
0 archive entries
VTP 6991 is a tube type in the TubeDatabase archive (class: 5" Tone Display Storage Tube). Recorded specifications: brand Vacuum Tube Products Co. Inc., construction Display / CRT, base Med Shell Diheptal, socket Diheptal, and maximum plate voltage 12000 V. The archive does not yet hold a photographed example of this type.
BrandVacuum Tube Products Co. Inc.
Class5" Tone Display Storage Tube
BaseDiheptal
Filament6.3 V @ 0.6 mA
Construction
Primary TypeDisplay / CRT
EnvelopeGlass with Aluminized Standard P20 phosphor
Base MaterialMed Shell Diheptal
SectionsWriting gun and flood (viewing) gun
Filament / Heater
Heater NotesBoth writing gun and viewing gun heaters are 6.3V, 0.6A.
Absolute Maximum Ratings
Plate Voltage12000 V
Grid 2 Voltage500 V
Grid 1 Voltage-200 V
H-C Voltage125 V
Audio Performance
Key Features
- Ability to display tones
- Write, hold and erase at operator's option
- High brightness for daylight viewing
- Fast writing and erasure speeds
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Writing Gun | -1400 V | — | 5000000 | — | — |
| Viewing Gun | — | — | — | — | — |
Application Notes
Zero volts is the black storage condition. Normal usage is to increase storage mesh positive approximately 20 volts to erase, then reduce to approximately zero volts, placing screen in the unwritten condition.
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