NE-51 Neon Bulbs

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he 1950s/1960s as an indicator lamp (on/off) at about the time that radio m anufacturers started to become concerned about user-servicing and hot-chass is radios - something that never really bothered them in the past. The work ed on the theory that a neon lamp was far less likely to burn out than the old standby #44 or #47, so that loose fingers were less likely to get nippe d. ASIDE: Audio devices held on to incandescent lamps (With specific refere nce to the 47) well into the 80s, before shifting - very slowly - to LEDs o r Fluorescent lamps. But, they had transformers on board to isolate the cha ssis.

only one post will light. It will trip (glow) at about 90V +/-.

220 or 240 V - that is voltages outside of Japan and the Americas. As sup plied, it has a 100K resistor in series with the lamp. For conversion to 22 0V, I have heard values of up to an *additional* 220K in series. Try there and work back if you wish to operate at 220V.

familiar with, and keep a bunch of these lamps in my spares-box.

Yes antique radios. I like them to with filaments glowing in the tubes.For younger members the tube is old glass bulb valve with the led on top. Some of them have the magic green eye for RF strength if you are lucky enough to find one. Neat trick that you can do with the old variable capacity plate tuner. Charge it to 30 volts with a neon bulb across. When you turn the tun ing knob to open the plates the neon bulb will flash? With only 30 volts ho w could it flash a neon bulb with a 80 volt trigger voltage?

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heathjohn2
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tuner. Charge it to 30 volts with a neon bulb across. When you turn the tuning knob to open the plates the neon bulb will flash? With only 30 volts how could it flash a neon bulb with a 80 volt trigger voltage?

I wish I'd thought of doing that. But I'm amazed it works, even with beautifully cleaned insulators on your capacitor.

Good demonstration of relationship between charge, voltage and capacity. (Analogue of skater's pirouette?)

Mike.

Reply to
MJC

Great analogy. The more I think of it the hands and feet coming in for a faster pirouette is exactly the same.

Reply to
John Heath

Kind of you to take an interest! The whole project was carried out in

1964 (when I became 21). The neons were directly driven via a diode array which encoded from up to ten numeral lines per digit. But I don't remember whether we fitted all those diodes (I still have circuit diagrams squirreled away!) into the display box or whether the cable has 5x7x4 wires, one per neon. There was a much bigger box which held the rest of the circuitry and the large battery...

Mike.

Reply to
MJC

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