How do I prevent this circuit from becoming "Active" during power-up?

Thread Starter

mprowe

Joined May 17, 2019
11
Thank you NoPoke,
Lots of useful tips. I like
[warming the TRIAC will make it more likely to flash on turn on which can help with tedious on off testing.]
... and for the next project of this type, I'll make life simpler for myself and use:
The dV/dT rating of the MOC is a lot higher than the chosen TRIAC, given that the load is*tiny* the MOC can probably drive it all on its own. 20mA is not a lot.
... or one of these:
f all else fails try replacing the MOC and TRIAC with a SSR like one of these https://www.openhacks.com/uploadsproductos/g3mb-ssr-datasheet.pdf
~M
 

ci139

Joined Jul 11, 2016
1,898
just noticed ? "3W LED bulb" . . . doing some math : 3-ac has 1.5 V ON-drop at (? ... 12V 21/5W ≈ 2A) , 3W / 240 V.RMS ≈ 12.5mA.RMS ← it is just about the Hold Current of your BTA/BTB06-xxxTW variant /!\ but also the range of gate control current (5mA for 'TW variant ← you likely have to route this in parallel with your load) . . . but that 5mA will be extracted from 12.5mA.RMS 17.7mA.SineAmplitudeValue ← it is a challenge to put the thing condugting just near/below it's ratings
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& don't miss the -- #18
the quadrants are different + some may require control voltages below V.T1 (Cathode)

← i guess they have Q.1 and Q.2 labels swapped here /!\ (about detailed)
src. :: Designing MCU applications for use in high voltage environments: Part 2 - Embedded.com
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useful stuff ::
http://class.ece.iastate.edu/ee330/miscHandouts/PowerThyristorApplicationNotes.pdf
http://www.icbase.com/File/News/download/ON_Reference_1.PDF
Non-insulated SCR / Triac control circuits Application note AN3168 ← has the correct quadrants' labelling
Thyristors & Triacs - Ten Golden Rules for Success In Your Application
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Your MOC3043M Poor Simulation of the Zero-Cross-Switching Emulator
 
Last edited:

visionofast

Joined Oct 17, 2018
106
I may not get the exact meaning of your question,but I think there's an element called thermal switch that you can make delay or prevent hazardous switchings in your circuit mechanically,if it's boring to be designed electrically ...
 

Thread Starter

mprowe

Joined May 17, 2019
11
Thanks cl139, a lot of very useful stuff here.
I do like the simulator. Tried to get to grips with Ngspice (integrated into Autocad's Eagle PCB software) but have failed miserably!!
A couple of quick questions, while I try to understand the "bigger picture", if I may?
  1. 1. The GND node between 625k & 5M resistor. Where is that "grounded"?
  2. 2. The two bridge rectifiers and related resistors. Are they representations of the Zero Crossing Circuit (ZXC) that is in a MOC3043M? But as the simulator does not have an MOC3043M, you have had to reflect it in an equivalent way?

  3. ~M

 

ci139

Joined Jul 11, 2016
1,898
? ( by the way Falstad is a bit idealistic/simplified simulator -- not too good for complex circuits -- unless you know how to trick it to "work")opto-3ac.png
 
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