Hi Neil,

No, square wave is OK. But if you have a DC source and you want an AC
square wave, you either need 3-terminal DC (positive, ground, negative)
and two switch elements, or an H-bridge. Either one will allow you to
alternate positive and negative excitation of your EL-wire. DC or DC
switched on and off will rot your EL-wire.

Removing the rectifier from a photoflash and taking the output straight
from the transformer will be sub-optimal. The positive and negative
voltages are not balanced because the transformer is driven by one
transistor(with corresponding weird duty cycle. It will work OK but is
hard on the EL-wire, which doesn't last all that long anyway.

Best regards, Bob

On Thu, Nov 19, 2015, at 09:13 PM, Neil wrote:
> Oh, you mean sine-wave then I guess?
>=20
>=20
> On 11/19/2015 11:40 PM, Bob Blick wrote:
> > Switching it on/off is not AC.
> >
> > BB
> >
> > On Thu, Nov 19, 2015, at 07:14 PM, Neil wrote:
> >> Hi Bob,
> >>
> >> I was suggesting that I'd generate DC with the LED driver and then
> >> switch that on/off rapidly to get the 1KHz-2Khz AC (though square wave=
).
> >>
> >> Cheers,
> >> -Neil.
> >>
> >>
> >> On 11/19/2015 12:46 AM, Bob Blick wrote:
> >>> Hi Neil,
> >>>
> >>> I've experimented a bit with this, and one thing I found is that EL w=
ire
> >>> really likes AC, like push and pull that is fairly well balanced. DC =
and
> >>> chopped DC don't work very well.
> >>>
> >>> Best regards, Bob
> >>>
> >>> On Wed, Nov 18, 2015, at 08:59 PM, Neil wrote:
> >>>> So I've got an EL driver that I want to use for a wearable, but it's
> >>>> bulky for that purpose, and I need something very thin.  Seems the
> >>>> battery and transformer are the larger parts of the whole driver
> >>>> module.  I decided to redesign it with a LiPo, but it seems that all=
 the
> >>>> EL driver circuits I'm finding have transformers.  The EL-wire spec =
is
> >>>> 90-120V at 1Khz-2kHz.  Couldn't I use a high-voltage LED driver for =
this
> >>>> purpose?  Something like Fig 8 here...
> >>>> http://www.monolithicpower.com/DesktopModules/DocumentManage/API/Doc=
ument/getDocument?id=3D3473
> >>>>
> >>>> I'd still have to throw an oscillator in there to modulate the LED
> >>>> driver, so I'll have to experiment to see if the LED driver can swit=
ch
> >>>> on/off that quickly.
> >>>>
> >>>> Anyone know of a simpler way to do this?  Or maybe even a very thin =
(say
> >>>> few mm tall) transformer that can work for this purpose?
> >>>>
> >>>> Cheers,
> >>>> -Neil.

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