Tube-number record
QT1257
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BrandEnglish Electric Valve Company Limited
ClassCold Cathode Touch Button Tube
BaseOctal
Construction
Primary TypeOther / special
EnvelopeGlass
SectionsSingle
Filament / Heater
Absolute Maximum Ratings
Plate Voltage325 V
Cathode Current25 mA
Audio Performance
Key Features
- Self-indicating electronic switch
- Actuated by touch
- Emits visible glow
- Cold cathode
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Maintaining | 80 V | — | — | — | 10 mA |
| Load Conditions | — | — | — | — | 15 mA |
Application Notes
Commonly used in lift control panels (e.g., Otis) for floor selection. Activated by body capacitance when the external control electrode is touched.
Datasheets
Datasheet: QT1257.pdf
Download PDFLoading datasheet...
Datasheets courtesy of Frank Philipse via Frank's Electron Tube Data Sheets.
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