I'm running the bakatronics kit with the 2.2 cap and the only thing I noticed is my element range seems to be from about 10%on to 90% on. I can't shut it all the way down or get full power from it.
GregKelley said:Thanks for the update, Walker. So back to the drawing you have under your red comment. You are talking about the 33μF cap, right? The negative side should connect to the negative side of the power source and the other side should be connected to pin 6 on the 555 timer? I guess I have mine turned around as well. I have a blue cap with a black stripe. I'm assuming that stripe is the negative side? The circuit seemed to work a little weird in testing but I chalked that up to the LED on the SSR not properly showing how the circuit was working.
Yup. The grey stripe should be to the negative voltage node of the circuit and the non-Grey side connected to the chip. You have it backwards.
Flip it around and it should work perfectly.
The circuit does appear to work better from observing the LED on the SSR. But now I've observed something else odd. It appears that it takes 3-5 minutes for the circuit to get going. When I enable power to it, it does not turn on the SSR at all. A few minutes later and it works fine. If I kill the power and then re-apply the power, the circuit works fine. Do I have a bad capacitor that is taking too long to charge up?
Great You have pointed me in the right direction...
Thanks
TD
Just wanted to bump a great thread, and also share a link the the Bakatronics PWM circuit I built into my control panel today. I wouldn't have been able to do it without the great info in this thread.
I built the circuit earlier this week and tested it using a computer case fan and 12VDC power supply and it worked great, so I wired and mounted into the control panel today. One thing I did notice is the circuit never gives you 100% Off or 100% On, it's more like 5% power and 95% percent power when the knob is turned all the way off or on. Not a big deal to me, but I just thought I'd point it out.
https://www.homebrewtalk.com/f170/m...-pid-ssr-build-281085/index5.html#post4232969
Thanks everyone!
That's great! I love my electric system. I too noticed that these PWM devices are never 100%. So I put in a switch that allows me to by pass the circuit and supply either 5v or 0v consistently to the SSR. It is a 3 way switch that will send all voltage to the SSR, send the voltage to the PWM or not send anything at all. I turn it full on until I have a rolling boil, then I switch it to run through the PWM.
I have my board all put together, but when I test it the light on the ssr stays on longer when the dial is turned down. It's as if something is reversed and when the dial is turned all the way up, the element is heating less if that makes sense. Any idea what the problem could be?
You have the left and right connections on the potentiometer switched.
That was the problem. Thanks for the quick response!
Here is a pic of three of them fully assembled and hot-glued..
this would be an "dc to ac" ssr correct?
Yes, as the previous poster noted. DC is fed to the control side of the SSR. The AC voltage passes through the switched side.
i worded that wrong. what i meant was the ssr must be dc on the pwm side and ac on the hot side. correct?
So i bought all the components from mouser to build walker's pwm. I have it all assembled and hooked up to my ssr. The ssr I have has an led indicator light. My question is should this light be blinking at a rate that matches how far up I turn the pot. Right now once I turn the pot on the light goes on steady.
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