The IV-12 (“NB-12”) is a large seven segment VFD tube produced in Soviet Union by Reflector (known today as Sovtek). It closely resembles the IV-11 but lacks a decimal point and has solid pins instead of flying leads. This allows the tube to be installed in a common 10-pin socket still being produced in China. Like most VFD tubes, the IV-12 includes a grid that can be negatively charged to interrupt electron flow without disabling the filament. This capability allows for multiplexed operation (see schematic shown below) and effectively turns the tube into a triode.
To my knowledge, the IV-12 is the largest VFD in a standard tube envelope.
Key Specifications
| Property | Description |
|---|---|
| Manufacturer | Reflector |
| Time period | 1970s |
| Digit height | 20mm |
| Envelope diameter | 22mm |
| Envelope height | ~58mm |
| Socket | Dekal |
References
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