Neon Lamp Circuits – Working and Application


A neon bulb contains neon gas at low pressure, enveloped in a glass capsule. Neon lamp Circuits emit light when electric light passes through the gas. These lamps widely used in neon signboards.

The neon lamp is composed of a sealed glass bulb containing two electrodes and a low-pressure noble gas mixture. The gas immediately surrounds the negative electrode as current flows through the lamp. These lamps glow usually orange in color but not very bright. The main application of a neon bulb is in the form of indicator lamps.


Neon lamp practically behaves like an open circuit when the low voltage supply because the resistance between the electrodes is so large.  When voltages increase gas inside the neon lamp begins ionizing and becomes extremely conductive.

Due to this conduciveness, the gas starts producing a radiant illumination from around the negative electrode. In case the inert gas happens to be neon, the emitted light is blue.

How neon lamps work

Neon lamp working


Initially, the neon bulb remains in breakdown position when there is no voltage or low-level voltages that are unable to trigger the glowing effects. As this breakdown position is struck, the lamp is triggered into the glowing mode and voltages drop across the neon terminals. Increasement in current fill the negative

Increasement in current fills the total area of the negative terminal. The additional escalation in the current drive the non into an arcing situation, in which the glow illumination turns into a blue-white colored light on the negative point and start producing rapid degradation of the bulb.

So you must attach a sufficient voltage for the lamp to save,  for the protection to fire neon bulb attach a sufficient resistance in the series.

Neon Breakdown Voltage

Commonly the breakdown or firing voltage of a neon bulb is approximately 60 to 100 volts. The continuous current rating is between 0.1 and 10 milliamps generally. The series resistor value should be according to the input voltage normally in European countries’ input voltages are 110 and in Asian countries voltages are 220 so you must use resistance according to voltages.

When it comes to neon lamps being controlled with a 220AC supply, a 220k resistor is usually good.

Simple Neon Bulb Circuits

In the above discussion, we have understood the working and characteristic of this neon bulb. Now we decorate this type of lamp for fun in a different style.

Neon Lamp as a Constant Voltage Source

Neon Lamp constant voltage feature normal light conditions we have to apply a voltage stabilizing unit which is shown in the pics given below.


Flasher Circuit Neon lamp

In this circuit, we are going to flash our neon lamp with the help of a capacitor, a diode, and a resistor. This circuit includes a 1M resistor, diode IN4007, and a capacitor 400v.

We have attached a resistor in series and a diode to convert AC into DC and then attach a capacitor to store current. The neon bulb is attached to the capacitor parallel. When the capacitor is charged through diode and resistor neon bulb turn on and capacitor discharge this process repeats again and again.


Neon Lamp Flasher Circuit

Flashing speed can be increased by changing the value of the capacitor.

Random Multiple Neon Flasher

This circuit is designed in such a way that each neon lamp will glow randomly. The pattern of glowing can be changed by changing in capacitors. This circuit flashes the neon bulbs like a skylight (cloudy lights).

Random Neon Flasher

Components for Random Neon Flasher

  • R1=1M
  • D1= IN4007
  • C1= 2.2uf 400v
  • C2= 4.4uf 400v
  • C3= 6.8uf 400v
  • N1,N2 & N2= Neon Bulbs

Neon Lamp Circuits Tone Generator

In this design of the neon lamp generates tone with the vibrator. This is a genuine signal generator circuit, the output could be listened through headphones or a small loudspeaker, to generate tone suitable use potentiometer.

Sequitional Flasher using Neon Lamps

Neon Flashers can be designed as random flasher as well as a sequential flasher. In the given below diagram, we have designed a flasher by using neon lamps sequentially.


More stages can be made by using same pattern. In this way, neon flasher can be designed in many ways.

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