Narrow-Bandwidth Television Association

I have been experimenting with different types of lights with High voltage flyback transformer .

In the photos i am using a 50v 20MA old light globe i got 30 years ago (took me this long to play with it !)

But got it to light via the spark i tried it with a few other newer lower voltage ones and had no luck lighting them so far ,i have never seen this done before apart from fluros neons never with a filament globe .

One i got a sort of dull green glow at best i am thinking it must have a tiny amount of some gas init ....tried some broken filament light bulbs ,i was expecting a spark across the broken filament but nothing again at best i could see the electrons just filling all the space in the globe trying this .

BTW as i found out any closer than 30cm taking photos or more so video the camera plays up

How does the brightness of the bulb compare with running it at its rated 50V? i.e. what proportion of its rated 20mA do you estimate is being drawn?

Given that you are using flyback EHT, it worries me that potentially lethal amounts of current are available. EHT current is normally measured in µA!

harry dalek wrote:In the photos i am using a 50v 20MA old light globe i got 30 years ago ...
...tried it with a few other newer lower voltage ones and had no luck lighting them so far...

Eee they dunt mek 'em like that t'day!

(apologies to Tony Capstick)

Dave Moll wrote:How does the brightness of the bulb compare with running it at its rated 50V? i.e. what proportion of its rated 20mA do you estimate is being drawn?

Given that you are using flyback EHT, it worries me that potentially lethal amounts of current are available. EHT current is normally measured in µA!

Hi Dave

Well the problem is i don't have a 50 volt power supply to check with i recall years ago trying to light it never got it to that brightness again i didn't have a power supply high enough i checked this experiment with another rated 48 volts and got it to light as well.
.

It was nothing more than playing around as i expected a broken lamp to spark across the broken filament that got me to try this just to see i suppose it needs a gas to do this so no lightning in a vacuum .

If the spark distance is 1mm per 1000 volts ? i would say this is doing around a 10 mm spark at best i would not want to be hit by it ...deep burns yakes and worse thats why i called this post playing with fire .

I have to to say about the experiment it works only on sparking.

I had to edit this post the two other low voltage globes i tried were broken looks like the filaments are ok but checked with the old multimeter and are dead ...

Mind you don't set anything on fire... I was playing silly buggers with a flyback transformer lighting up old mains neons and melted some wires in the process...

M3DVQ wrote:Mind you don't set anything on fire... I was playing silly buggers with a flyback transformer lighting up old mains neons and melted some wires in the process...

The few wires that you wrap around the the fly back connected to the Mosfet they get pretty warm if you just spark to ground i can see this would not be good doing this for a long while ....with the light globe between it seems to be no problem for the circuit and wires .I would say this is more my luck than design .



No worries i take care when working with flybacks always better safe than sorry .

I tried replacing the 555 timer with my high frequency stepper motor dc motor generator and that works but not as good as the timer sparks a lot smaller .

Boy! I haven't seen one of those bulbs in many a year! 50V, 20mA, made for manual telephone exchanges, i.e. those with an operator, The telephone system then (and now) still uses 50V as a supply, chosen from the requirement of using four 12V Lead-Acid batteries in series when the power fails.

Emergency calls (999/911) must get through even when there's no power. Every household should have at least one basic land-line telephone that doesn't need power. No cordless etc.

When you have no power and the batteries in your mobile are dead, you can't beat the POTS to make that call.

Steve A.

POTS = Plain Old Telephone System.

Steve Anderson wrote:Emergency calls (999/911)

Hasn't the rest of the world fallen into line with us yet!? (000)

Steve Anderson wrote: Every household should have at least one basic land-line telephone that doesn't need power. No cordless etc.

Well, our delightful *minority* government (note: minority meaning they have no mandate for ANYTHING) has ordained that we are not allowed to have copper lines any more - we are going all fibre! via it's 90 Billion dollar (unfunded) NBN (National Broadband Network) white elephant. So there goes the copper landline - there goes the powerless emergency communication system, people will be forced to use UPS systems.

There is, of course, no physical reason to turn off the copper system - except it would represent a competitor.

Now, how to get down off this soap box?...

gary wrote:Hasn't the rest of the world fallen into line with us yet!? (000)

In some countries 000 is the international access code, e.g. 000 44 etc.. for the UK. In the UK it's 00 612 etc (I think) and here it's 001 44 etc..

Anyway, I digress again...

Steve A.

I find it interesting that the US has the strange code of 911 which just happened to eventually coincide with the day of one of their most infamous emergencies (even though they have the day/month backwards).

It is unfortunate that it also exemplifies the TV brainwashing of our youth that it is often inadvertently dialled here instead of 000 - there has even been talk of having 911 reach the same connection.

... but I digress even further...

Well Steve just call me a hoarder I always wondered where that globe would of been used in now i know after all those years .

I got it from a electronics surplus place for !0 dollars they would send you a box of old Ic's transistors light globes resistors so on it was a nice box of pot luck for that price and those globes were in it i lost a lot over the years .

By the way Gary i finally got one of those little geared motors out of a micro wave oven good for the camera experiments .

Talking about that microwave oven i scrapped i found this light globe in it good for the high voltage test its a 250 volt 25 W the spark needs about this distance for this one to give this brightness about the best this can do on the 12 volt power supply ,the timer and mosfet are on the same supply ...i was thinking if it will light a 50 volt globe should partly light something like this..

Interesting colour for the glowing filament.

It looks mauve, is that how it appears to the eye or is that a camera artefact?

Cheers,

Graham

AncientBrit wrote:Interesting colour for the glowing filament.

It looks mauve, is that how it appears to the eye or is that a camera artefact?

Cheers,

Graham

I didn't notice that ...it could be the camera is seeing something we can't as you think ....the filament just looked a normal orange as i recall but i will check this .
I suppose it does look like a uv light this colour in the photo.

Harry,

I admire your experimenter's spirit.

Amazing what you keep coming up with.

Regards,

Graham

AncientBrit wrote:Harry,

I admire your experimenter's spirit.

Amazing what you keep coming up with.

Regards,

Graham

Thanks Graham i Start off doing one thing and trying to do this leads on to something else i drive my self nuts as i get interested in to many things at the same time ,i am a hopeless case i know