Indicators and Small Discharge Lamps
Small gas filled indicator lamps have been used for decades. These offer low power consumption, long life and compact sizes. The neon indicator is still in common use for mains supplies due to their higher running voltage compared to LEDs. Indicators of colours other than orange can be achieved with argon and fluorescent coatings as shown on the right. Many different special applications can be found using low pressure noble gasses including camera xenon flash tubes.
Spark gap voltage regulators can use gas fills at different pressure to select particular breakdown voltages for circuit protection. These are often found in telecommunication equipment where external wires may be prone to inductive pickup.
Numerical displays before LED and LCDs often used gas filled numerical indicator tubes known as Nixi tubes. Counter tubes with pin indicators were also popular, these are known as Decatrons. These were also neon filled.
Other examples shown are Xenon strobe tube, Gas filled fluorescent tube switch starter, large Argon filled indicator lamp, Decatron counter neon tube as uses in scaler counters.