On Thu, 20 Mar 2008 15:52:52 +1100, Franc Zabkar
put finger to keyboard and composed:

On Wed, 19 Mar 2008 20:57:29 +0000, Baron
put finger to keyboard and
composed:

Another thing I noticed was
that the output capacitors, there is two in series for each lamp, seem
to be very small values. They are marked 18J 3Kv. I assume that is
18pf 5% 3000 volts working.

An 18pF capacitor would have an impedance at 100kHz of 100Kohm

If 100Kohm were in series with the lamp, then the lamp would be
drawing a miniscule amount of current.

- Franc Zabkar

After some research, it appears that 18pF makes sense.

The following datasheet uses an example with a 50kHz resonant
frequency, 5mA operating current, and a ballast capacitance
of 22pF:

http://focus.ti.com/lit/ds/symlink/ucc3972.pdf

The lamp specs (for a notebook) a

Lamp Length 250mm (10”)
Lamp Diameter 6mm
Striking Voltage (20°C) 1000V (PEAK)
Operating Voltage (5mA) 375V (RMS)
Full Rated Current 5mA
Full Rated Power 1.9W

Sorry for my error.

- Franc Zabkar
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