Message 25457 in TECH.WW
From: G8MNY
Date: Tue, 07 Jul 26 06:27:00 Z
Newsgroups: TECH.WW
Subject: Thermostatic Soldering Iron LED
Message-ID: <64330_GB7CIP>
Path: N2MH4|GB7BED|EI2GYB|GB7CIP
R:260707/0632Z 33375@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260707/0632Z 13961@GB7BED.#21.GBR.EU LinBPQ6.0.25
R:260707/0631Z 56117@EI2GYB.DGL.IRL.EURO LinBPQ6.0.25
R:260707/0627Z @:GB7CIP.#32.GBR.EURO #:64330 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Mar 11)
(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
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 and stops mains
reverse voltage appearing across the LED. The value of 33R is selected so that
the LED is not lite with just 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
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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