Rpi 4 specifies 5.1V 3A PSU. This is 15.3W ability not fully used. At least not all of the time or without heavy peripherals.*
Your Fluke meter shouldn't have gone off scale in Ampere series measuring mode. Maybe there is a shorted or reversed end plug/cable?
Dummy tests for this kind of rail & load range take three 4.7Ω/10W resistors. One pulls 5.1V/4.7Ω=1.085A. Paralleling a second one pulls 2.17A. Paralleling a third one pulls 3.255A.
Those tests aren't sustainable with small on board Q2 heatsink for long. Short time tests only. But if passed without considerable rail dropping and LEDs not extinguishing it means there's no problem with your PSU configuration & parts even for 3A peaks and bit more.
*RPi Power Benchmarks
Your Fluke meter shouldn't have gone off scale in Ampere series measuring mode. Maybe there is a shorted or reversed end plug/cable?
Dummy tests for this kind of rail & load range take three 4.7Ω/10W resistors. One pulls 5.1V/4.7Ω=1.085A. Paralleling a second one pulls 2.17A. Paralleling a third one pulls 3.255A.
Those tests aren't sustainable with small on board Q2 heatsink for long. Short time tests only. But if passed without considerable rail dropping and LEDs not extinguishing it means there's no problem with your PSU configuration & parts even for 3A peaks and bit more.
*RPi Power Benchmarks
Hi,
I've soldered most parts except for a missing IC1 regulator. But I also realized I forgot any thermal pads or paste between the heatsinks and rectifiers/transistor(Q2). I only want to confirm that I really need the thermals, then I will try to arrange it without desoldering...
EDIT: just read the guide again and understand that it is not needed when sinking is done on board. Correct?
I've soldered most parts except for a missing IC1 regulator. But I also realized I forgot any thermal pads or paste between the heatsinks and rectifiers/transistor(Q2). I only want to confirm that I really need the thermals, then I will try to arrange it without desoldering...
EDIT: just read the guide again and understand that it is not needed when sinking is done on board. Correct?
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I looked through and did not see anything about this - is there a way to get 24 volts?
I want to build a supply for the SOTA Condor motor controller and think L Adapter would be good if this might be possible.
Please excuse if this is the 88th time you have answered this.
Thanks, Salas
PS now I see the post where the fellow is using the L ADAPTER to power an amplifier (I think it was) and your only concern was current through the LEDs.
This supply will supply 1 A current at most - that was the value of the wall wart supplied with it.
Would lowering the value of the current set resistor for LM334 be advised?
This will not need to be adjustable so I will not use the specified LED block.
Do you have a favored single LED?
I want to build a supply for the SOTA Condor motor controller and think L Adapter would be good if this might be possible.
Please excuse if this is the 88th time you have answered this.
Thanks, Salas
PS now I see the post where the fellow is using the L ADAPTER to power an amplifier (I think it was) and your only concern was current through the LEDs.
This supply will supply 1 A current at most - that was the value of the wall wart supplied with it.
Would lowering the value of the current set resistor for LM334 be advised?
This will not need to be adjustable so I will not use the specified LED block.
Do you have a favored single LED?
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Hi, the answer is also in the pdf guide:
"The jumper should only be moved in parallel to the LEDS across the two rows of pins.
Not vertically on single row. No jumper at all allows for all the LEDS to operate when the
transformer has enough output. Each added LED contributes about 1.75V extra. 17.5V total +
2.5V from VR1 maximum. For >20V needs, using 2kΩ VR1 can extend Vout to 27.5V max."
Lowering of the LM334's current set resistor is not advised. That decreases its current source impedance, it's no good.
Favored single LED hmm... HLMP-6000 is supposed to be a really low noise type. Although it has an unusual form factor.
"The jumper should only be moved in parallel to the LEDS across the two rows of pins.
Not vertically on single row. No jumper at all allows for all the LEDS to operate when the
transformer has enough output. Each added LED contributes about 1.75V extra. 17.5V total +
2.5V from VR1 maximum. For >20V needs, using 2kΩ VR1 can extend Vout to 27.5V max."
Lowering of the LM334's current set resistor is not advised. That decreases its current source impedance, it's no good.
Favored single LED hmm... HLMP-6000 is supposed to be a really low noise type. Although it has an unusual form factor.