Hi, Welcome to EasyEDA. ### Please note that the link to AN-3006 that you have posted is to an insecure site. The correct link is this: https://www.fairchildsemi.com/application-notes/AN/AN-3006.pdf #### About your circuit: First off, the schematic you have drawn is incomplete so you will not get signals from it like those in AN3006. You have to make up your mind about what you are trying to do here. Make a simulation of the circuit in AN3006 or make a squarewave oscillator using a 555 timer? The two things are *very* different. To get you going, here what I suggest you do. If you are new to simulation and you want to try simulating a circuit you need to: 1. read some background info first; 2. start with a simpler example such as a 555 timer configured as an astable; 3. build up to the full simulation in steps. #### How to do that? 1. Read and try to fully understand: https://en.wikipedia.org/wiki/555_timer_IC, https://www.fairchildsemi.com/datasheets/LM/LM555.pdf and http://www.ti.com/lit/ds/symlink/lm555.pdf; 2. Pay special attention to the note about PCB layout and power supply decoupling; 3. Note that without a special circuit "trick" you cannot set up a 555 timer to generate a squarewave. The "conventional" circuits will always have a longer rise than fall time on the voltage across the timing capacitor; 4. Then learn about simulation in EasyEDA, start here: https://easyeda.com/forum/topic/How_to_find_simulatable_parts_in_EasyEDA-1YgasK2kC; #### Note that although there is now a spice symbol for the MOC3023 opto triac in: `System Components > Spice Miscellaneous` the spice model does not yet work correctly in ngspice. BTW, this example does show a way to get a squarewave out of a bipolar 555 timer: https://easyeda.com/editor#id=04b2d5d6afa8466dbe5c368bf5ff5e7f|cac20e037ab8498a8bab0c8d84c67bbe (A CMOS part can be used without the diodes and the pot - just using the single resistor - to give a nearer to ideal 1:1 duty cycle but it will still not be exact.)

There are now fully functional spice symbols for the MOC3023M and MOC3021M opto triacs in: `System Components > Spice Miscellaneous` Have fun and post back if you get stuck. :)

@components @andyfierman thanks for the reply and all the tips - this is still useful for me however as i will now try to at least see if the circuit i have built is probing the same as a simulated circuit. also yes thanks for the link, i thought that was just my comp as i have all the good malware running on this thing lol. the circuit is decoupled as it is running though a two out transformer 10v and 24v - so my aim here was to trigger the 555 from the 10v rectified and run the triac from the 24v for a solder iron. yes my main issue presently is that the probe out results are much different from the AN-3006 so i think my solution here is try to find something common, and to do that i will try to build the circuit in your very useful software and then see at least if what i have here built is doing close to the same thing as what the simulation says. then i have something common, that will tell me where it has deviated from the AN-3006, yes really what i'm trying to achieve is the AN-3006 zero crossing. indeed i plan to play with just square wave generation from different timers, i'd just like to get this iron going. i'm aware i can just use a 'dimmer switch' (triac setup) out from the 24v off the transformer but that will hardly help me learn really. @Components my biggest mystery as a learner of the AN-3006 is D5 actually (D5 1n5248) there is no ref to it in the note and it makes little sense to me. i think i will work the moc20~ into the circuit once i have found something common. then i can see what effect it is having. thanks for all the help and tips, I'll struggle though this ha ha, and if all else fails 'dimmer switch' regards.

`...the circuit is decoupled as it is running though a two out transformer 10v and 24v...` I think you are confusing `isolation` with `decoupling`: https://easyeda.com/andyfierman/Power_supply_decoupling_and_why_it_matters_-451e18a0d36b4f208394b2a2ff7642c9 https://en.wikipedia.org/wiki/Decoupling_capacitor https://www.youtube.com/watch?v=VfCu-siq0-Y&authuser=1

D5 is an 18V zener diode. It is incorrectly labelled as 11V but is referred to in the section: `Current Limiters` on bottom left of page 2 of AN-3006. To get your sim going, you can use the BZX84_C18 spice symbol in: `System Components > Spice simulaton > Spice discrete` You'll find a spice symbol for at least one suitable Triac in the same section. See: https://easyeda.com/editor#id=e489d5386099453088cf12a162d270d3 for a demo of Triac models.

@andyfierman ah yes i see - thank you for the correction i'm on an exponential learning curve and am also translating human language (which is designed backwards) I have now understood the Zener and so called 'decoupling' i now have an inverted 'equalization' (EQ) (what humans call 'current') and have understood the aspects of that so i have learned a lot. also have learned about the '555' thanks for telling me about the 18v 11v discrepancy . your software is useful and thanks for being so interactive.