30W-15W soldering iron switchbox

hi i'm fish and i got this idea from a friend of mine, a somewhat down converter for a 30W soldering iron to 15W. temperature controlled stations costs too much for me as i am only starting in this field. the original idea was to insert a diode between one of the conductors in the heating element. my friend suggested that maybe we can do a switchbox with LED indicators instead to preserve the soldering iron.

here is what we did so far...

**broken link removed**

-this is for a 220 AC voltage.
-the diode is the 1N4004
-using a DPDT on/off/on switch to bypass the diode on high position
-we tried resistors with values at 3.3K but it got fried.
-what resistor values will we use for this circuit to work?
-is it gonna work to begin with?
-what do you think?

i'm new to these so please bear with me a little.




fish

Perhaps you could try a light dimmer - I've heard that they work quite well for hot glue guns / low-power soldering irons etc.

after this one, probably. my mind is set on this one for now. if this is going to be "do-able".

I am by no means an expert, but I don't think you can use the diodes and resistors like this - the power dissipated would probably make them pop (fail, explode)! Perhaps try googleing "soldering iron temperature control circuit". You would probably use a TRIAC to controll the iron rather than resistors. Note that temperature controlled stations a more than just adjustable temp irons. The bits are almost always of better qualioty (than cheapie irons) and generally use 24V instead of 230V (better for sensitve electronics, apparently)

No, I don't think your suggested circuit is safe or functional. Try googling for schematics, when you understand how they work, you would have a better shot at making your own.

By introducing the diode into the circuit you effectively reduce the voltage to the iron to 1/2. That will give you a 7.5 Watt iron. You will need about 155 V at the iron to get it to 15W. An 800 Ohm/10 Watt resistor would do instead of the diode. You should also place reverse voltage blocking diodes across the LEDs. E

thanks mike for your input. i appreciate it.

canadaelk said:

By introducing the diode into the circuit you effectively reduce the voltage to the iron to 1/2. That will give you a 7.5 Watt iron. You will need about 155 V at the iron to get it to 15W. An 800 Ohm/10 Watt resistor would do instead of the diode. You should also place reverse voltage blocking diodes across the LEDs. E

Click to expand...

thank you E.