Ignition coil for flashtubes as HV transformer?

[Jan Panteltje]

Ignition coil for flashtubes as HV transformer?
I want to make a few hundred volts at very low current, a few uA.
These trigger tubes for flash tubes seem to do 200V in 4000V out,
by discharging a cap in the primary. They are dirt cheap here.
So the transformer ratio is 1 : 20.
I am thinking about PWMing one to make 500 V peak from 5 V DC.
As I do not have one yet, does anybody know the inductance of these things?
I used one a hundred years ago in a flash tube trigger circuit...
Should have measured it..

 

[Jan Panteltje]

An easy source of trigger transformers is disposable cameras - but the
transformer is tiny.

Photography shops return the disposable cameras to the factory for recycling
and in the UK they get around £50 for a sack full.

Some shops will let you scrounge a few cameras to experiment with, others
charge between £0.50p & £1 per camera.

Yea, but I was thinking a bit larger production.

 

[Jan Panteltje]

I measured an old Ford ignition coil a few years ago and the turns
ratio seemed to be about 100:1. A 1 volt sinewave gave me about 100
volts out with no load, but I forgot what frequency I was using. I
think the primary inductance measured around 10 millihenrys. You get
about 2 amps in 2 milliseconds from 12 volts and a 1 ohm primary coil
resistance. That's about 5000 RPM and 8 cylinders. Lower RPM is more
current and energy.

-Bill

Those are car ignition coils, I know about those.
I was referring to flash tube ignition coils.
Those are tiny, 10 mm length, 8 mm diameter.
Anyways I found some data, 16.5 turns .25 mm diameter primary,
500 turns .07 mm diameter secondary,
9 kV max secondary without corona or sparks, 4 kV nominal, 200V primary.
Looks like I have to order a bunch.
Less than an Euro in quantity.

 

[Spehro Pefhany]

Those are car ignition coils, I know about those.
I was referring to flash tube ignition coils.
Those are tiny, 10 mm length, 8 mm diameter.
Anyways I found some data, 16.5 turns .25 mm diameter primary,
500 turns .07 mm diameter secondary,
9 kV max secondary without corona or sparks, 4 kV nominal, 200V primary.
Looks like I have to order a bunch.
Less than an Euro in quantity.

http://www.mouser.com/catalog/specsheets/XC-600020.pdf

1.69 EUR in 10's. Looks like they're obsolescent.



Best regards,
Spehro Pefhany

 

[SoothSayer]

http://www.mouser.com/catalog/specsheets/XC-600020.pdf

1.69 EUR in 10's. Looks like they're obsolescent.



Best regards,
Spehro Pefhany

Probably SMD mount versions now.

 

[Jan Panteltje]

http://www.mouser.com/catalog/specsheets/XC-600020.pdf

1.69 EUR in 10's. Looks like they're obsolescent.

Right, these have a bit higher turns ratio it seems.

I can get other ones from www.conrad.nl for 1.33 Euro a piece, less for per 10, even less for per hunderd.
http://www.produktinfo.conrad.com/d...144-da-01-en-ZUEND_SPULE_FUER_BLITZLAMPEN.pdf
Type item number 542144 in their search window for prices, and they ship free above 25 Euro.
For > 1000 directly to source probably 25 cents?
I tried to find some diodes on mouser.com last night... and gave up.
Could not get their 'filter' to work in my browser, digikey worked OK.

BTW do you know if PIC 18F14K22 will be continued for long time?

 

[Spehro Pefhany]

Right, these have a bit higher turns ratio it seems.

I can get other ones from www.conrad.nl for 1.33 Euro a piece, less for per 10, even less for per hunderd.
http://www.produktinfo.conrad.com/d...144-da-01-en-ZUEND_SPULE_FUER_BLITZLAMPEN.pdf
Type item number 542144 in their search window for prices, and they ship free above 25 Euro.
For > 1000 directly to source probably 25 cents?
I tried to find some diodes on mouser.com last night... and gave up.
Could not get their 'filter' to work in my browser, digikey worked OK.

BTW do you know if PIC 18F14K22 will be continued for long time?

No idea, but generally Microchip seldom obsoletes parts and when they
do there's usually a direct replacement. What's the difference between
the 18F14K22 and 18F14K22T? The latter seems slightly cheaper.



Best regards,
Spehro Pefhany