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G8MNY > TECH 04.03.11 08:56l 52 Lines 2094 Bytes #999 (0) @ WW
BID : 9250_GB7CIP
Read: GUEST
Subj: Thermostatic Soldering Iron LED
Path: IZ3LSV<IV3YXW<HB9TVW<ON4HU<DB0RES<ON0AR<UA6ADV<GB7CIP
Sent: 110303/2351Z @:GB7CIP.#32.GBR.EU #:9250 [Caterham] $:9250_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
By G8MNY (Updated Jul 09)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
This circuit is suitable "Magnetic Curie Point" temperature switch controlled
mains irons! The LED lights up when the Iron is plugged in & is drawing current
in its heat cycle it goes out when it is up to temperature. It also works on
some internally electronic controlled 24V irons too.
Also shown is a static earth, that keeps the stray tip voltage down to about
12V AC MAX, while still giving an un earthed iron for work on live circuits
(~100V) safely.
CIRCUIT
Fuse ON
LÄo-oÄÄÄÄo\oÄÄÄÄÄÄÄÄ¿ Temp
250mA )|| ÚÄÄÄÄÄÂÄÄÄoÄÄÄÄÄÄÄÄÄÄo_oÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
LED )||( 10k Switch Curie ³
ÚÄ´<ÃÄ¿ 230V)||(24V ÚÄ´ :...Magnet Iron 12R Element
³ ³ )||( ³10k Bit 48W
ÃÄ´>ÃÄ´ )|| ÀÄÄÄ)ÄÁÄÄÄoÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
NÄÄÄÄ´ ÃÄÄÄÄÄÄÄÄÙ ³ ³-----------------------------iron earth
ÀÄ33RÄÙ ³ 1M If 3 wire
EÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÙ
The LED is connected to the mains neutral, but even so good insulation is
needed! The bypass diode connected the reverse way is a 1N4001 & stop mains
reverse voltage appearing across the LED. The value of 68R is selected so that
the LED is not lit with the transformer magnetising current.
If the 50Hz flashing LED is anoying, blows up the LED, or is not bright enough
try this more complex circuit instead...
LED
ÚÄ´<ÃÂÄ´<ÃÄ´<ÃÄ¿
³ ³100u+³ ³ Here the 15R is selected for brightness & unlit LED
ÄÄ´ ÃÄÄ´ÃÄ´ ÃÄÄ when the iron is not on. The 100uF protects the LED
ô>ÃÄ)ÄÄÄÄÄÙ ³ from the spiky power up surges as well smooth out
³ ÀÄÄÄÄÄÄ´>ÃÄ´ the 100Hz LED DC power. Diodes are all 1N4001.
ÀÄ15ÄÄÄÄÄÄÄÄÄÄÄÄÙ
Also see my Tech Bul on "Soldering Iron Economiser/Boost"
Why Don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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