This may be the most complex grow light ever; it's certainly the most complex one I have ever seen.

 

Yes I agree on that, the amount of components needed is a lot more than any other I had seen too. But this wonderful design have more feature than them. I am ready to assemble them tonight and hopefully the sun shine bright enough for me to test it out. Been raining every morning and night recently over my place here.

By the way tracecom, is this circuit after all the change still have the frequency pulsing over 720 hz? How to actually compute the math to check on that frequency pulse value?

 

By my calculations, the duty cycle is 60.66% on at 2.36 kHz.

The formula is frequency = 1.44 / ((R1 + R2 + R2) * C).

 

By my calculations, the duty cycle is 60.66% on at 2.36 kHz.

The formula is frequency = 1.44 / ((R1 + R2 + R2) * C).

I see, base on Post #194, it suppose to be 25% duty cycle at 750Hz. Unless I missed out some post on that.

 

I see, base on Post #194, it suppose to be 25% duty cycle at 750Hz. Unless I missed out some post on that.

I wasn't following the thread at that point, so I can't say. I can calculate some new values for R1, R2, and C1 if you like.


ETA: Looking back at 194, I do remember that; I even breadboarded the circuit. But since then, the component values were changed and the pots eliminated. I don't know when or why exactly.

 

Yes I am not sure either. Maybe when Bernard is online he can tell us that.

R1 and R2 to 10k ohms, C1 to 68nf and C4 to 10nf can set it to around 720hz right? I am not sure on duty cycle calculation.

 

Yes I am not sure either. Maybe when Bernard is online he can tell us that.

R1 and R2 to 10k ohms, C1 to 68nf and C4 to 10nf can set it to around 720hz right? I am not sure on duty cycle calculation.

It calculates to 705.88 Hz with a 66.67% duty cycle. C4 plays no part in the frequency or the duty cycle.

 

I did a google search just now and found that they included C4. That's the problem with google sometime. I have many invalid answer in my brain lol.

 

With R1 = 5600 and a 1N4148 in parallel, R2 = 18000, and C1 = .047 μF, the frequency calculates to 736.5 Hz and the duty cycle to 23.7%. Is that close enough?

 

With R1 = 5600 and a 1N4148 in parallel, R2 = 18000, and C1 = .047 μF, the frequency calculates to 736.5 Hz and the duty cycle to 23.7%. Is that close enough?

Yes that should be good enough to try out first. Thanks again tracecom. And also for duty cycle, how do you calculate them?

 

95 ohms is not a standard value; are you using 91 ohms or 100 ohms or what?

Yes I am using 100 ohms cause there is no 95 ohms, but it was posted that value.

 

Yes I am using 100 ohms cause there is no 95 ohms, but it was posted that value.

Okay, I will add that to the schematic. Bernard should be here soon, and will settle the question about the 555 timing, and I will make whatever changes are required there, and elsewhere, and repost the design.

It's 6:34 am on Friday here; what time and day is it in Singapore?

 

Okay, I will add that to the schematic. Bernard should be here soon, and will settle the question about the 555 timing, and I will make whatever changes are required there, and elsewhere, and repost the design.

It's 6:34 am on Friday here; what time and day is it in Singapore?

Hi good morning tracecom, it is 8:54PM Friday night here.

Anyway I found the formula for duty cycle in this forum which is
Duty Cycle = (R1 + R2)/(R1 + 2R2)
after calculation I got 56.73% and not that you mentioned 23.7% just now. I am confuse again lol. Anyway never mind that first, I assembling the circuit now with what is in the schematic first.

 

Hi good morning tracecom, it is 8:54PM Friday night here.

Anyway I found the formula for duty cycle in this forum which is
Duty Cycle = (R1 + R2)/(R1 + 2R2)
after calculation I got 56.73% and not that you mentioned 23.7% just now. I am confuse again lol. Anyway never mind that first, I assembling the circuit now with what is in the schematic first.

To get a duty cycle of less than 50% requires a diode in parallel with R2; the diode's anode should be connected to pin 7 and the cathode to pins 6/2. Then, the formula is Duty Cycle = R1/(R1 + R2).

 

tracecom- Beautifull! My boss once said that a "commettie" would pick a well laid out ckt. with, neatly drawn schematic with questionable operation over a tried & true ckt with dangling leads & chicken scratch [ mine ] schematic. Both comparators are powered by battery. but will take a little time to check.
jenovauh, put 39 in calc. & divide by increasing numbers untill result is close to 5, 39/ 7= 5.57, close; 30/8= 4.87, close enough; 1/4W X 8= 2W.

 

Okay thanks tracecom, i am still assembling the circuit. it is so challenging for me to complete it. Anyway when I am done, i will post picture and hopefully you can check if I had done it wrongly. I think I will lol.

 

555 timing got lost along the way, I should have picked up on it, but go back to post # 194, pg. 20. R2= 43k, R3= 130k, D1, & C = .01, all close to std values. Measured times .33 ms, & 1.33 ms total period = 751.8 Hz.
Have to go now to free dinner.

 

My boss once said that a "commettie" would pick a well laid out ckt. with, neatly drawn schematic...

Yeah, but don't forget that a camel is just a horse designed by committee.

555 timing got lost along the way, I should have picked up on it, but go back to post # 194, pg. 20. R2= 43k, R3= 130k, D1, & C = .01, all close to std values. Measured times .33 ms, & 1.33 ms total period = 751.8 Hz.
Have to go now to free dinner.

Eat enough for me, too.

My calculations may be wrong, but take a look at the figures below. The duty cycles are essentially the same, but the frequency seems too low with the 43k, 130k, and .01 μF. But maybe I'm missing something.

 

Okay thanks tracecom, i am still assembling the circuit. it is so challenging for me to complete it. Anyway when I am done, i will post picture and hopefully you can check if I had done it wrongly. I think I will lol.

It helps me a lot to print a copy of the schematic, and then use a highlighter to mark each part and each wire as I put it in.

 

Thanks for the advise. By the way the 3rd Boost Buck (charger) need to set out to how much voltage?