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G8MNY > TECH 25.04.24 03:02z 95 Lines 4781 Bytes #29 (0) @ WW
BID : 5710_GB7CIP
Subj: 12V Fluorescent Tube Inverters
Path: SR8BBS<SR4BBX<SR1BSZ<IW0QNL<JH4XSY<N3HYM<VE3CGR<KA1VSC<WW6Q<PE1RRR<
VK2RZ<GB7CIP
Sent: 240418/0906Z @:GB7CIP.#32.GBR.EURO #:5710 [Caterham Surrey GBR] $:5710_GB
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
Here are 2 designs:-
From Chrissi ZR6CBP
Very Easy Fluorescent Tube Inverter Circuit 12V DC to 220V AC 6 Ä 20 W
(corrected by G8MNY 08/06)
+ 12 V
ÚÄÄÄÄÄÄÄÄÄÄÂÄÄÂÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³³ ÚÄÄÄÄÄÄÄÄ¿
10K ³ ³ ³ ³³ / ³³
³ 555ÚÄÄÁÄÄÁ¿ / ³³ \ ÚÁÁ¿
ÃÄÄÄÄÄÄÄ´7 8 4³ 12V \ ³³ / 220V ³ ³
\ ³ ³ 1A / ³³ \ ³ ³
1M /<ÄÄÂÄÄÄ´6 ³ \ ³³ / ³ ³
\ ³ ³ ³ / ³³ \ ÀÂÂÙ
ÃÄÄÄ´2 3ÃÄÄÄ¿ c³ ³³ / ³³
0.1Ä ³ ³ ³ / b ³/ ³³ ÀÄÄÄÄÄÄÄÄÁÙ
0.001 === ³ ³ \<ÄÄ100RÄÄÄÄÄÄ´
³ ³ 5 1 ³ / R TIP ³\
³ ÀÄÂÄÄÂÄÙ \ 4K7 41 e³
³ .01=== ³ ³ ³
ÀÄÄÄÄÄÁÄÄÁÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
(Modification from Eric ON4CBL)
Tune 1M for +Ä 10 kHz, & maximum efficiency / resonance from transformer.
Tune 4k7 for desired current / brightness.
Heatsink TIP 41 for currents > 300 mA.
----------------------------------------------------------------------------
From : VK3EUB.#MEL.VIC.AUS.OC (Brian)
This circuit appeared in silicon chip mag October 1999 page 75
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ 6 T ÀÄ¿ ³ ÚÄÙ ÚÁ¿
³ feedback Ä´ ³ ÃÄ ÚÅÄÅ¿
³ ÚÄÙ ³ ÃÄ ³ÀÄÙ³
safety ³ ÚÄÄÄÄÄÄÄÄÄÄÙ ³ ÃÄ 960 T ³ ³
resistor ³ ³ ³ ÃÄ secondary ³ ³
+12VÄÄÄÄÄÄÄ´ 3R ÃÄÄÄÂÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ ÃÄ ³ ³
³ ÚÁ¿³ ³ 20 T ÀÄ¿ ³ ÃÄ ³ÚÄ¿³
³ ³ ³³470R ³ primary Ä´ ³ ÃÄ ÀÅÄÅÙ
100æF + ³ ÀÂÙ³ ³ ÚÄÙ ³ ÀÄ¿ ÀÂÙ
16 VW ÄÁÄ ÃÄÙ ³ b ÃÄÙc ÀÄÄÄÄÄÄÄÄÄÄÄÄÙ
ÄÂÄ ³ ÃÄÄÄÄÄÄÄÄ´ 15W or 18W
Ä ³ ÄÁÄ ÄÁÄ Ã>¿e BD681 fluorescent
³ ÄÂÄ ÄÂÄ ³ tube
³ ³0.0012 ³0.022 ³
0VÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÁÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÙ
This fluorescent light inverter uses just one transistor & a transformer wound
on a ferrite rod. The clever component is the transformer, it performs 3
functions. Firstly, it acts as a feedback component for the transistor to
create an oscillator circuit. Secondly, it provides a high voltage (over 2kV)
to strike the fluorescent tube & thirdly it supplies energy to keep the tube
illuminated.
The transformer has 3 windings. The 20 turn primary is switched by the BD681 &
the resulting primary voltage of around 24V peak to peak (plus considerable
spikes) is stepped up in the 960 turn secondary. Positive feedback is applied
from the third winding to the base of the BD681 to ensure that the circuit
oscillates continuously.
The ferrite core of the transformer is an antenna rod from a transistor radio.
You can use a slab antenna but i chose to use an antenna rod 6cm long & 9mm in
diameter.
The primary winding is the first to be wound, on 45mm of the rod, using 20
turns of 0.5mm diameter enamelled copper wire. Use grease-proof paper as the
interlayer insulation. The second winding is the feedback winding & consists of
6 turns of 0.3mm wire wound in a spiral fashion so that it lies over the full
length of the primary winding.
The secondary winding consists of 960 turns of the 0.3mm wire. The feedback
winding must be connected the right way around so that the BD681 gets positive
feedback. When first powered up, connect the 3ê safety resistor in the positive
line & connect the feedback winding. Then turn the circuit on & off very
quickly & if the fluorescent tube does not come on immediately, the feedback
winding is the wrong way around. The safety resistor allows a limited current
to flow through the circuit & the BD681 will not be damaged.
Once the correct feedback connection has been established & the fluorescent
light comes on correctly, remove the 3R resistor & the circuit is ready to
use. However, you must not use the circuit without the fluorescent tube
connected because it provides loading for the transformer & has a damping
effect on the spike voltages to the transistor's collector each time it
switches off.
By J Draper, Glenview, Queensland Australia.
Why don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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