Glowing Neon Lights Run on Gas Instead of Electricity
In the annals of electronic history, the NE-2 neon bulb stands as a testament to innovation and versatility. First introduced in the 1960s, this humble device found widespread use in various applications, thanks to its unique properties and capabilities.
E. Norbert Smith, in a 1965 article for "Elementary Electronics" magazine, extolled the many uses of the NE-2 neon bulb. With thousands of potential applications suggested, the NE-2 proved itself to be a versatile component in the realm of electronics.
One of the key factors that set the NE-2 apart was its high trigger voltage (approximately 90 V) and holding voltage (around 60 V). This made it suitable for power pilot lamps and fuse-blown indicators, as it could reliably operate on standard line voltages like 120 V.
The NE-2's most distinctive feature, however, was its negative resistance region. When lit, the bulb exhibited a unique electrical behaviour that allowed it to be part of relaxation oscillator circuits, useful for timing and clock functions even before the advent of LEDs and digital electronics.
Moreover, some neon bulbs could be designed to act as logic gates or switches, expanding their utility in early electronic control circuits. This bistable operation capability, coupled with additional control electrodes, made the NE-2 a valuable asset in early electronic systems.
Beyond simple illumination, the ionizable neon gas in the bulb enabled it to detect external influences such as light, microwaves, or electrostatic fields. This multi-functionality extended the NE-2's applications beyond mere indication, highlighting its versatility.
Variants of neon discharge devices, like nixie tubes, were even used as numeric displays in the pre-LED era.
Smith's article also detailed a 50 V regulated power supply circuit, which could be used for higher voltage needs or improved regulation performance. Neon bulbs found primary use as indicator lamps before the advent of the LED, but they continue to find practical applications even today.
Many cheap AC socket testers still employ a neon bulb to indicate the presence of a capacitor. Although negative resistance can still be achieved with special diodes and certain transistor operating regimes, an active switch is more commonly used for oscillator circuits today.
The NE-2 neon bulb's unique electrical and physical properties made it robust, reliable, and multifunctional for lighting, indication, sensing, and timing tasks. It bridged the gap between simple indicator lamps and more complex electronic components, serving as a vital link in the evolution of electronic technology before LEDs revolutionized low-voltage lighting and displays.
The NE-2 neon bulb, showcased in E. Norbert Smith's 1965 article for "Elementary Electronics" magazine, was more than just a simple indicator lamp. Despite the arrival of LEDs and digital electronics, it found practical applications in various gadgets and technology, such as AC socket testers, due to its multi-functionality. In the realm of electronics, it served as a versatile component, capable of acting as logic gates or switches, and even used in relaxation oscillator circuits for timing and clock functions.
