driving glow-starter with very low voltage
Posted: Mon Jun 13, 2022 6:51 am
For those using the glow-starter bulbs from fluorescent tubes, I found an excellent way to drive them with low voltage: EL wire drivers.
EL wire is electro luminescent wire. it is available at electronic hobby shops, online etc. the wire has a central wire conductor, an insulating sheath with phosphor material, conductive sheath of fine wire, topped with transparent insulation. People use it for decorative lighting including wearables. it requires about 15mA per meter of length.
https://www.youtube.com/watch?v=RJ2xGFfrND0
Anyway, we are not so interested in the wire as the drivers.
The EL wire requires AC voltage of about 80+ volts from 50 Hz to circa 10khz.
Small packaged ac inverter drivers are available running on AA batteries, but I guess can easily run on 5V usb etc. cost is just a few dollars, even under a dollar on aliexpress for 12v powered ones.
I bought this one locally and it gave the measurements indicated further down this post:
https://www.jaycar.com.au/el-wire-power ... t/p/SL2440
not sure what voltage and frequency this aliexpress one operates at but I guess it
https://www.aliexpress.com/item/1005003 ... 2484%21sea
I tried driving my usual fluorescent tube glow-starter (Sylvania FS-14) which has hydrogen and argon lines, so it's very useful, although the h alpha line is rather bright compared to the argon. usually I am driving this with 240v and a series resistor of about 24kohm (more or less, I can't remember). Obviously, i don't like having 240v on the mount outside potentially in wet conditions so I was considering using a 12v-240v inverter as per Christian Buil's recent posts, but stumbled on the EL wire inverters. The series resistor prevents the bimetallic strip switch in the calibration lamp from switching off.
It works fine and no series resistor seems to be required as the current seems to be sufficiently low to not activate the bimetallic strip.
Output voltage of this EL driver is 120V AC when running from 2xAA 1.2V NiMh cells. Rated load on the label of the inverter is 150mA @3v DC. my multimeter measures 14kHz as the frequency but I need to recheck this with an oscilliscope as am not certain about the frequency range of the meter. I was not able to measure the AC current through the glow tube, I guess because my meter isn't able to measure current at such high frequency.
Given that I normally use the calibration lamp for only a few minutes per night, I may not even bother wiring it up to a power supply, in order to avoid the potential injecting 14khz ripple back into other equipment which may not like that sort of disturbance.
So, low cost, intrinsically safe driver for glow starter tubes, and no series resistor required, what's not to like?
EL wire is electro luminescent wire. it is available at electronic hobby shops, online etc. the wire has a central wire conductor, an insulating sheath with phosphor material, conductive sheath of fine wire, topped with transparent insulation. People use it for decorative lighting including wearables. it requires about 15mA per meter of length.
https://www.youtube.com/watch?v=RJ2xGFfrND0
Anyway, we are not so interested in the wire as the drivers.
The EL wire requires AC voltage of about 80+ volts from 50 Hz to circa 10khz.
Small packaged ac inverter drivers are available running on AA batteries, but I guess can easily run on 5V usb etc. cost is just a few dollars, even under a dollar on aliexpress for 12v powered ones.
I bought this one locally and it gave the measurements indicated further down this post:
https://www.jaycar.com.au/el-wire-power ... t/p/SL2440
not sure what voltage and frequency this aliexpress one operates at but I guess it
https://www.aliexpress.com/item/1005003 ... 2484%21sea
I tried driving my usual fluorescent tube glow-starter (Sylvania FS-14) which has hydrogen and argon lines, so it's very useful, although the h alpha line is rather bright compared to the argon. usually I am driving this with 240v and a series resistor of about 24kohm (more or less, I can't remember). Obviously, i don't like having 240v on the mount outside potentially in wet conditions so I was considering using a 12v-240v inverter as per Christian Buil's recent posts, but stumbled on the EL wire inverters. The series resistor prevents the bimetallic strip switch in the calibration lamp from switching off.
It works fine and no series resistor seems to be required as the current seems to be sufficiently low to not activate the bimetallic strip.
Output voltage of this EL driver is 120V AC when running from 2xAA 1.2V NiMh cells. Rated load on the label of the inverter is 150mA @3v DC. my multimeter measures 14kHz as the frequency but I need to recheck this with an oscilliscope as am not certain about the frequency range of the meter. I was not able to measure the AC current through the glow tube, I guess because my meter isn't able to measure current at such high frequency.
Given that I normally use the calibration lamp for only a few minutes per night, I may not even bother wiring it up to a power supply, in order to avoid the potential injecting 14khz ripple back into other equipment which may not like that sort of disturbance.
So, low cost, intrinsically safe driver for glow starter tubes, and no series resistor required, what's not to like?