LCD Backlights
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 ...
1/(2.pi.f.C)
= 1/(2 x 3 x 10^5 x 18 x 10^-12)
= 1/(108 x 10^-7)
= 100Kohm
If 100Kohm were in series with the lamp, then the lamp would be
drawing a miniscule amount of current.
- Franc Zabkar
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