NEON NOVELTIES

A collection of circuits & info' using the neon lamp

Neon Lamp V-I curve (click to enlarge)


When used as a simple power on indicator, the neon needs about 0.2mA current, and show about 80 volt across its terminals.
Use formula below to calculate value of limiting (ballast) resistor.



Relaxation Oscillator
I believe so-called because the stored charge on the capacitor is "relaxed" once the neon lamp strikes at about 90 volt D.C.
Produces a Sawtooth type output voltage.
I used this type of circuit in the Magic-Eye demonstration to make the M-E's flick



Neon relaxation oscillator used for simple CRO timebase generator. (click to enlarge)

The flashing neon can be front-panel mounted
Indicates "power-on" before CRT warms up.
Square Wave Oscillator

The 1K/22K resistive divider and diode 'clamp' the max o/p at approx 5 volt.
"Ring" Oscillator


Ring oscillator driving incandescent lamps using SCR's



Lt Uhura comm's panel on "Starship Enterprise"
I always thought the erratic flashing light panels on Lt Uhura's console were made by a neon ring oscillator ?
As per circuit above.



Neon Voltmeter
Ex Australian Radio Television & Hobbies Mag Sept' 1964