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[email protected] pfjw@aol.com is offline
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Default NE-51 Neon Bulbs

On Friday, November 20, 2015 at 3:55:22 PM UTC-5, Madness wrote:
Just acquired a bunch of these lamps. They're in the same mini-bayonet
style as lamps like the #44/47. But would anyone know if these lamps can
be connected directly to 120 volts? Or do they need a resistor, @ if so,
what value?


Mpfffff....

This lamp was used by Zenith and more than a few other manufacturers in the 1950s/1960s as an indicator lamp (on/off) at about the time that radio manufacturers started to become concerned about user-servicing and hot-chassis radios - something that never really bothered them in the past. The worked 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 nipped. ASIDE: Audio devices held on to incandescent lamps (With specific reference to the 47) well into the 80s, before shifting - very slowly - to LEDs or Fluorescent lamps. But, they had transformers on board to isolate the chassis.

It is designed to operate at ~120V AC. It _CAN_ operate at ~120V DC, but only one post will light. It will trip (glow) at about 90V +/-.

Unless there is a voltage dropper in the circuit, it will fail quickly at 220 or 240 V - that is voltages outside of Japan and the Americas. As supplied, it has a 100K resistor in series with the lamp. For conversion to 220V, I have heard values of up to an *additional* 220K in series. Try there and work back if you wish to operate at 220V.

As about 2/3 of my hobby time is dedicated to vintage radios, I am quite familiar with, and keep a bunch of these lamps in my spares-box.

Peter Wieck
Melrose Park, PA