In SX Microcontrollers, SX/B Compiler and SX-Key Tool, johncouture wrote:

Ok here are the results of the first experiment and I need help from you electronic gurus.

The datasheets, schematic and program are attached.  The reason for the TLP630 optoisolator and 2N6071A triac are that I happen to have them on hand.  If swaping out the parts will solve the problem, that's fine too.

When R3 on the attached schematic is 20K ohms,

     value   ON         OFF

R3  20K  chatters   full off

R3  10K  full on      chatters

 

Thus, my problem is that the valve chatters.  If I use a 20K resistor, it chatters in the ON position, if I use a 10K, it chatters in the OFF position.  Using a POT does not seem to make any difference, it just exchanges behavior at about 12K.

It seems the chatter means that the resistance is too high to be fully on but not high enough to be off.  

The optoisolator alone is 256 ohms.

Thus, do I need to put another transistor in there?  I tried a 100uf cap between pin 4 and 5 of the optoisolator but, as you can tell, THAT was a shot in the dark (I had to feel like I tried SOMETHING).  All that happened with the 20K resistor it just chattered in both positions.

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