Jfets can be measured with Ohmmeter for RDS. With one probe on gate and source pins at the same time. The other probe on drain pin.
Read post #1 footnotes. As for M1... IRF9610 can replace FQP3P20 if no more than 1A CCS is set.
Ok. So I installed new M1 from second kit bag . Installed 22ohm ( nearest value i jad ) dummy resistor . Decrease trimmer to 0 ohm . Now I have 11.44v DC output . No led lit.
R1 = 1ohm , voltage across it 470mv.
Voltage across R8=340mv.
Nothing across R5,6,4,7
Voltage on M1 between GS 0.59V
Voltage on M2 between GS 3.29.
I have built L-adapter on friday and it worked straight no issues. Where is the problem here ?
Pulled all Q and J look ok . Is 75k plus 10k trimmer too much of a resistance to drop voltage . And why led's aren't working ?. I am making order from mouser looks as j113 is the only option .
I mean its a realitively simple build . Anything else i should add to order ?
R1 = 1ohm , voltage across it 470mv.
Voltage across R8=340mv.
Nothing across R5,6,4,7
Voltage on M1 between GS 0.59V
Voltage on M2 between GS 3.29.
I have built L-adapter on friday and it worked straight no issues. Where is the problem here ?
Pulled all Q and J look ok . Is 75k plus 10k trimmer too much of a resistance to drop voltage . And why led's aren't working ?. I am making order from mouser looks as j113 is the only option .
I mean its a realitively simple build . Anything else i should add to order ?
Normally no problems when CCS to load ratio is proper, Ubib has been made and applied more than a lot of times by diyers. Static can kill Mosfets before or during assembly/rework is an odd problem or some small semi can die during soldering. Check if you have a broken LED issue too. The 3mm ones are sensitive to soldering power sometimes. When M1 properly conducts in this circuit should also show few Volt VGS.
Ok. Shame to say. I installed red led wrong way . Pulled them out , reinstalled properly . Installed 0.68 ohm back . Fit 10 ohm 5w . Power up ,adjust 7.5v all looks good . Lesson learned . Just one mosfet down . Thank you for your help Mr Salas. Just to be safe i leave it for a while 10w resistor reached 137 degress celcius after 10 min . Heatsink steady on M1 - 60 degrees. I will sink resistor and let it run overnight i think .
Sooooooo happy .
Will report after listening expect huge improvement over wall plug supply .
Sooooooo happy .
Will report after listening expect huge improvement over wall plug supply .
Always nice to know impressions in system applications. About your L-Adapter build too.
Hi Salas.
I posted about GLED431 reference mod few days ago.
Now i put back the standard R5 and R6 resistors (270R) and replaced generic red leds with HLMP-6000 leds. This is the best combination by far.
It seems that R5 and R6 values should be as they are. So standard reference is perfect!
I posted about GLED431 reference mod few days ago.
Now i put back the standard R5 and R6 resistors (270R) and replaced generic red leds with HLMP-6000 leds. This is the best combination by far.
It seems that R5 and R6 values should be as they are. So standard reference is perfect!
I picked some of these up. It's only been on for about 30 minutes or so, but after dialing in the temperature it has not budged at all.
Things may not be as stable as I was hoping, it did drop down about 0.5vdc after an hour, I readjusted and seems to be holding again. I'll go ahead cold start and leaving the psu on for half a day and checking in multiple times, repeat that across some days, see how things behave. Ambient temp is 20C.
Maybe different orientation of the bead and/or different cut lead length could help? Like how close or not is to the same temperature Δ affected area as the circuit's elements... It could even takes to try a few NTC of nearby specs to really nail it. Or different absolute value ones within a batch. But OK, if its surely better than without the specific NTC type's compensation those are very good news already.