Breadboard set by Geekcreit. Flat terminals are located at the joints of the cylinder; The next step was to apply a luminescent coating directly onto the glass of the lamp:
At the same time, the chassis became more technologically advanced in production – the indicator lamp could now be fixed along the front panel and easier to change when burnt out. Since the threads are connected in series, a break in one breaks the common circuit and the lamp becomes unusable.
The design was laborious and low-tech, so gas-discharge indicators were developed. In dynamics it looked something like this: We break the flask.
Converter circuit: Each set contains 10 boards of various sizes: 50x70mm(24×18 solder points), 40x60mm(20×14 solder points), 30x70mm(24×10 solder points), 20x80mm(28×6 solder points ).
Some of the details can be borrowed from the electronic ballast of a compact fluorescent lamp. Watering is usually not required.
Sometime before the war, the problem arose of fine-tuning the AM radio to the station with the volume control turned off, so as not to disturb those around you with a whistle of radio interference. The ones in which the wire figures were stacked:
Let’s take wire cutters and subject the lamp to final deconstruction.
VLI of the third generation also with a flat balloon. Tape leads can be gently bent, there is no substrate – it is glass. We use a flat bottle with a volume of 0.1 liters as the indicator body.
Under load, it drops to about 70V. Today we will feel Chinese fiberglass and assemble a seven-segment indicator from a bottle of (from) vodka and burnt out light bulbs. Now completely flat – the top glass is also simply cut from the sheet. The design of the gas-discharge indicator was also protected by a patent, and no one had the desire to pay patent royalties, but there was freed-up capacity for the production of lamps, so new indicators with extended viewing angles and low anode voltages appeared – vacuum luminescent. I recommend to buy.
Development of blue LEDs and UV radiation made it possible to create devices that emit white light and can replace incandescent lamps. This design greatly reduced energy consumption (due to operating voltages of 15-30V instead of 150-180), simplified the assembly of the indicator itself (by reducing the stack of parts from 27 to 3-5), the overall circuitry of the device (now 7-8 lines approached the indicator controls instead of 10-11) and improved visibility due to the location of all signs in the same plane (similar gas-discharge indicators were developed, but were not widely used).
Insert the plate into the bottle.
By the way. one of them, straight from the store, is already half-dead – out of four filaments, only two glow. In early examples, the glow of the crystals could be directly observed through a magnifying lens:
Carefully bend the leads of the filaments by 90 degrees, apply them with their flat side to the textolite.
Voltage converter details:
When the converter is powered by a single lithium battery, its output voltage at no-load reaches 230-250V. The pitch of the holes is 2.54mm.
Solder the wires.
What follows from this? It is possible to draw 70 volts out of 4 with a converter, but it’s better not to, if possible – you need to raise the input voltage of the converter.
Conclusion: Prototyping boards fulfill their purpose and allow reusing filament LEDs from burned-out lamps.
The color of the mask on the seller’s page is green, but it is sent randomly – I received white, yellow and red ones.
This is how the indicators of analog values ​​worked.
She will need to cut off the bottom as carefully as possible.
To speed up the experiment, I bought a couple of cheap filament lamps. And in its assembly, breadboards will come in handy for us. Assembled transducer:
On the inner contour
bottles we customize the cardboard template, cut out a plate of thin textolite on it. On a common glass substrate, there is a series of series-connected LEDs under a common phosphor layer: With the transition from octal lamps to finger lamps, the upper part of the lamp bulb turned out to be occupied by a getter and was opaque, so the funnel was replaced with a ladle:
Therefore, in the second
In the VLI generation, flat cylinders were used, made of sheet glass glued with a special mastic, where the top glass is convex.
If the gas-discharge indicator was a set of diodes in a common gas cylinder, then the vacuum-luminescent indicator was a set of triodes with a common cathode and grid and separate anodes coated with a phosphor. For a consumer solution, it turned out to be not very good: the dial indicator is difficult to manufacture, fragile due to the presence of moving parts in the design and greatly limits the designer’s imagination when developing the front panel. For the anode to glow, a positive potential must be simultaneously applied to it and to the grid. The accumulated experience of working with phosphors came in handy.
it was planned to break them from the very beginning. You cannot do without a converter.
Textolite thickness 1.6 mm, brand FR-4. Hello everyone. Although some of the LEDs in it remain operational, the design of the lamp does not provide for its repair.
In the plate we drill 6 holes with a diameter of 4 mm at a distance of 30 mm from edge to edge. The product was provided for writing a review by the store. From two batteries connected in series, it works much better.
Indicator in operation:
We fix them with electrical tape. In this case, the conclusions will pass into the holes and they will only have to be bent again and pressed against the textolite. The difficulty lies in the fact that the operating voltage of the thread is about 60 V – this is not very compatible with modern electronics, powered by voltages of 3.12 V. Therefore, in 1935, the first electronic light indicator appeared – a voltmeter-lamp. In fact, this is a triode, in which the voltage on the control electrode set the shape and area of ​​the anode section, on which the electrons did not fall and did not make the phosphor layer glow.
The voltage amplitude on a separate filament is 95 V. Cutting off the bottom of the bottle is easy. Use a pointer voltmeter? You can, and they did it in professional equipment.
Now you can poke into the LEDs with an oscilloscope. The parcel came in a gray polyethylene bag. The conclusions are located at the end of the lamp or at both ends. Assembly of equipment has become easier, but the problem with viewing angles has not gone away. How to assemble a non-vacuum fluorescent indicator

Each filament is a rigid LED strip with flexible leads for mounting.
Subsequently, to increase the size of the displayed digits, it was necessary to switch to a design with frosted light guides: In order to further reduce power consumption, I had to switch to LED seven-segment indicators.
And here is its driver. Well, in principle, you can tear out from here and use a diode bridge somewhere.
The lamp was placed in the standard connector of those times and displayed the signal level by the width of the luminous sectors inside the metal funnel, which could be looked into from the outside:
Now, instead of separate incandescent filaments, the gas around the wire electrode shone. To do this, you first need to draw a closed line along the glass with a glass cutter, and then simply press a steel wire red-hot with an electric current to it with the help of two pliers. VLI of the first generation had a cylindrical cylinder.
These are very lousy light bulbs, they flicker so that you don’t want to look at them. Review published in accordance with clause 18 of the Rules Now the indicator consists of sheet glass a little less than completely (with the exception of the stem), which reduces the amount of glass waste during manufacture. More indicator exotics can be seen here.
The length of the rigid part of the filament is 30 mm. To take advantage of the released production capacities, LED filament lamps were developed: These LED filaments can be used in structures as display elements – such an application does not require them to
work at full brightness, which in a nitrogen-oxygen atmosphere will be accompanied by overheating and will quickly finish them off. The design is difficult to manufacture, inconvenient during installation, sensitive to shock and shaking – the plate with anodes can break.
Inside two bags with latches, in which there are 40 boards of 4 different sizes. Let’s mark the polarity of the supply voltage directly on the substrates with a marker.
Due to the series connection of LEDs, the thread is powered by high voltage and low current, despite filling the lamp bulb with hydrogen, it heats up strongly during operation and therefore is relatively (with designs with normal heat dissipation) quickly fails. The task was reduced to indicating the voltage in the AGC circuit without special requirements for accuracy. A flat plate with anodes is placed inside the balloon, to which the rest of the electrodes are attached. Double-sided boards with hole metallization, contact pads are tin-plated. For digital indicators, initially, a package of sheets of transparent material with engraving was used, in which each sheet could be illuminated by a separate incandescent lamp: