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Topic: mosfet help (Read 1 time) previous topic - next topic

Runaway Pancake

"That"?  It's a representation of the SSR/module, emphasis on its input terminals.

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jimjam

Thanks ill give it a try

jimjam

I just setup this circuit and the pwm from the arduino is putting the correct voltages to the controller, but when I put a 100w lamp through the load of the controller it does not dim when I change the settings to the pwm pin. If i make the pin value 255 the lamp is on full brightness but when I go to any lower value the lamp seems to flash on and off very fast. also when I put my meter across the 2-10v terminals when there is load on the output the polarity reverses.

Runaway Pancake

#18
Feb 29, 2012, 07:01 pm Last Edit: Feb 29, 2012, 07:04 pm by runaway_pancake Reason: 1
I was wondering how that'd work.
I think the PWM freq and the mains freq are mixing.
Don't know about that "polarity reversal".  If it's hooked up right then there's nothing to reverse.  The 12V supply's ground and the arduino ground and the transistor ground are all in common (connected together)?

So, then, you need a clean, stable DC source for the control volts.
Like I mentioned last week, that could be based on filtering the PWM.
If you can devote several arduino output pins, you could effect a "crude" DAC [ http://www.asdlib.org/onlineArticles/elabware/Scheeline_ADC/ADC_DAC_ladder.html ].
You could buy a DAC IC and run that from the arduino.
"Hello, I must be going..."
"You gotta fight -- for your right -- to party!"
Don't react - Read.
"Who is like unto the beast? who is able to make war with him?"

Runaway Pancake

#19
Feb 29, 2012, 07:13 pm Last Edit: Feb 29, 2012, 07:21 pm by runaway_pancake Reason: 1
You don't need 60V, but...
http://www.arduino.cc/playground/Main/RegulatedPositiveVoltageBooster

http://digital-diy.com/swordfish-example/314-digital-to-analogue-conversion-dac-via-pwm.html
"Hello, I must be going..."
"You gotta fight -- for your right -- to party!"
Don't react - Read.
"Who is like unto the beast? who is able to make war with him?"

jimjam

I dont know if this means anything or not but I tried removing the power supply and wired the pwm pin straight to the triak and I still got the same results so maybe the problem is not the power supply. Perhaps i need to try it with a larger load perhaps a 100w lamp is too small for the triak to control.

Runaway Pancake

I dare say that's probably enough (1A).
I think it needs clean/stable DC (no raw PWM.)
"Hello, I must be going..."
"You gotta fight -- for your right -- to party!"
Don't react - Read.
"Who is like unto the beast? who is able to make war with him?"

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