# What is the difference ?

Discussion in 'Electronic Basics' started by [email protected], Sep 18, 2005.

1. ### Guest

Hi Good morning to group member.Can any member help me. I brough
a hobby kit to build a 20 watts flourescent light by car battery,
it turn on the light immediately when power is connected. But compared
to those energy saving light bulbs(actually is also with
flourescent tube inside the bulb)it only turn on slowly when power is
connected.I don't understand what is the different as both also driven
by electronic circuits,won't you thing the hobby kit is simple &
efficiency to turn the flourescent on ? thanks in advance.
Best Regards
Hoong

2. ### arem_29Guest

hello there!.. i hope ur doin fine.. im Ryan!.. well, regarding your
http://www.tpub.com/electronics.htm
the link provide electronic infos!... i hope it helps!...

5. ### dohiGuest

Hi, Hoong,

You've built an inverter circuit. This sort of circuit makes 200 volts or
higher / some kHz AC from 12V DC.
Those voltage and freq can light fluorescent light directly.
Energy saving light bulb has inverter circuit in it. That makes those
volt./freq. from 100-220V / 50-60Hz AC.
Then using energy saving bulb with your circuit is abnormal. It causes
damage both of bulb and your circuit.
Good Luck

dohi
from Tokyo

6. ### andyGuest

he's lying - it's just a spam site with nothing to do with electronics.

7. ### Guest

Thanks all for the information. Hi Dohi it seem that using higher KHz
can light
the flourescent tube, but what is the best Hz & voltage,does that mean
higher
is better & brighter ?

8. ### mowhoongGuest

Thanks all for the information. Hi Dohi it seem that using higher KHz
can light
the flourescent tube, but what is the best Hz & voltage,does that
mean
higher
is better & brighter ?

9. ### dohiGuest

-------snip-------

Hi, Hoong,

Using higher freq. than 50/60Hz is needed not for lighting, but for
preventing flicker.
Flicker is not good for your eyes. This is the purpose of the inverter
fluorescent light.
And higher freq. reduces the size of transformer in the inverter circuit.
Fluorescent tube can be lit even by DC if supplying voltage is high enough.
(Actually lighting by DC may cause some problem, but I'm not sure in it.)

Fluorescent tube is a sort of discharge tube.
It's not a conductive device then it doesn't go with Ohm's law.
When the supplying voltage is lower than a voltage, (discharge voltage)
Increase voltage over discharge voltage, increase load current drastically.
(and bomb!)
Inverter circuit for fluorescent tube develops some hundreds volts
when it's not connected to the tube. (voltage without load)
When it's connected to the tube and load current flows,
the inverter circuit drops the output voltage.
Then, if your inverter circuit has enough power,
your fluorescent tube lights brightest within the safety condition, I
think...

Any way, once the discharge current flows, the discharge voltage is
decreased, so the actual relation of load current and voltage is
much complex than my description.
I don't know the exact value of discharge voltage of fluorescent tube.

dohi