Need help to light up 8 LEDs with different color

tracecom

Joined Apr 16, 2010
3,944
SP = 5.97V
U2-1 = .091V
U2-2 = 5.96V
U2-3 = 2.47V
U2-4 = 0V
U2-5 = 4.22V
U2-6 = .091V
U2-7 = 5.96V
U2-8 = 5.97V

I don't see how U2-5 could be 8V; the only power on the board is from the SP, which is set at 5.97V. (B1 is still disconnected; is that the problem?)
 

tracecom

Joined Apr 16, 2010
3,944
I disconnected R19-2 from R100-2, and created a voltage divider to supply 4V to R19-2. Adjusted R20 until DA came on. Noted that once DA comes on, further adjustment of R20 will not turn it off; power must be disconnected from U2 and reconnected to "reset" U2-1.

Disconnected voltage divider and reconnected R19-2 to R100-2.

What's next?
 
Last edited:

Bernard

Joined Aug 7, 2008
5,784
I assume that you left R20 adjusted so that when R100-2 is at 4V , DA just switches on. Remember that as soon as DA switches R20 is effectivley out of the ckt.untill R100-2 drops to the ref. V of 2.5V [night].
If all other adjustments are still set, we should be operational.
If jenovauh can bring his ckt up to yours, then we have made progress. Seems that there was a problem with the battery picking up yhe load.
Is there any part that you do not understand?
 

tracecom

Joined Apr 16, 2010
3,944
I assume that you left R20 adjusted so that when R100-2 is at 4V , DA just switches on. Remember that as soon as DA switches R20 is effectivley out of the ckt.untill R100-2 drops to the ref. V of 2.5V [night].
I did leave R20 set.

If all other adjustments are still set, we should be operational.
If jenovauh can bring his ckt up to yours, then we have made progress.
Good.

Is there any part that you do not understand?
As you know, I am just a tinkerer, not an engineer. And even as a tinkerer, my op-amp skills are especially weak. So, I can't really say that I have a good handle on the operation of the entire circuit. Now that it seems to be working as you intended, maybe I can improve my understanding.
 

tracecom

Joined Apr 16, 2010
3,944
Here is the latest version of the schematic, Rev. A3. The only change that I have made to it without discussion is that I have reversed pin 1 and pin 3 on R20, R23, and R28. I did this in order to make the pots operate so that the voltage at pin 2 increases as the pot is rotated clockwise.

What needs to happen now is for Bernard to carefully recheck the schematic, and point out any and all problems, post the corrections and/or additions needed, and I will make them to the schematic and update the revision level to A4.

Only then should jenovauh make any changes to his breadboard.
 

Attachments

Thread Starter

jenovauh

Joined Jul 4, 2013
246
Thank you tracecom and Bernard, I will assemble the circuit the next day when I am free after work. Will report the result ASAP.
 

Bernard

Joined Aug 7, 2008
5,784
jenovauh, this might be a good time for you to make a list of all adjustable settings, and describe what each is suposed to do & what you think the set values should be. I think that this would help you to understand the workings of the ckt. We are still here to help with answers.
 

Thread Starter

jenovauh

Joined Jul 4, 2013
246
The reason I need to ask what is their set voltage it is because I don't even know now with all the changes and the design of how the circuit work. I can't be setting what I assume and killed all the components right?
 

Thread Starter

jenovauh

Joined Jul 4, 2013
246
I have deleted R100, and changed several of the component numbers so that they will be sequential. Attached is Rev. A4 of the schematic, and it is hopefully the last revision.
Hi tracecom, i am assembling the circuit and realize C7 value is 100pf, nf or uf? also Q4, not all the pins are connected.
 

tracecom

Joined Apr 16, 2010
3,944
Hi tracecom, i am assembling the circuit and realize C7 value is 100pf, nf or uf? also Q4, not all the pins are connected.
C7 is an electrolytic capacitor, and is 100μF; it should have at least a 25V rating; 35V would be better, and 50V would be okay too. Notice the polarity and be sure to connect the + side to R19-1 and the - to the ground buss.

On Q3 and Q4, pins 1, 2, and 3 should be connected together, pins 5, 6, 7, and 8 should be connected together, and pin 4 is the gate and is only connected as shown in the schematic. I have , modified the schematic to make this clearer.
 
Last edited:

Thread Starter

jenovauh

Joined Jul 4, 2013
246
Thanks for clarification tracecom. I had finally assemble the circuit. It is night time now. So i will wait for tommorrow morning and see what happen. Anyway the green LED is always on, is that normal?
 
Top