New to Edaboard - looking for direction/help with simple variable power circuit

Greetings Edaboard !

My name is Tyler and I am new to the board and electrical design in general.

I am attempting to build a 'simple' AC 120v circuit that will allow me to control the power flowing through a ceramic heating element.

The idea is based off a cheap variable temperature soldering iron I tore apart. Upon destruction I found that the circuit uses a potentiometer with a triac and diac to adjust the power to the ceramic element.

I have some ceramic elements I bought from HongKong via ebay and don't have any info on what power ratings they can handle. The elements have four wire leads coming out of the ceramic package which is considerably diferent than the two leads coming off the soldering iron element... this confuses my feeble little mind.

What I am looking for is help with finding resources to design/build a replica of the circuit. I hear Spice is the program of choice to design electronics?

What other resources are recommended for the begginer attempting to design/build ones first circuit?

Tools at my disposal are: soldering iron, multimeter, bread board, small amount of ca$h, internet.


Many thanks to those who help, I'll be posting pics of the frankinstiened soldering iron, hongkong elements, and general stuff I am playing with tonight...

Smile on
-Tyler

You can buy a simple lamp dimmer for 120 V AC and use it; such dimmers are made for resistive loads which your heater is.
You can build such simple dimmer but the cost of components usually is higher than the cost of a nice dimmer which was built to safety requirements. Only check the maximum allowed power when you buy the dimmer or a triac if you want to build one.

---------- Post added at 21:43 ---------- Previous post was at 21:41 ----------

To find the power of any resistive (heater) element measure its DC resistance with your multimeter. It can vary +/- 20-40% with temperature, usually growing up a bit. From the resistance calculate the current for 120V AC maximum.

Thank you for the reply Jiripolicka,

I would simply buy another soldering iron or dimmer circuit however, I would like build my own from scratch... something about full DIY is attractive to me.

Thank you for the hint on how to measure DC resistance and thus find AC current!

I wish you a good luck with building your dimmer, only please, be VERY CAREFUL in operating an open circuit under 120 V AC and possibly a high-power heater load!

From my own experience with 220V AC, I blew a number of thyristors and triacs, also capacitors and even wires. Fortunately, I survived. But this work is still dangerous.

Good luck!