--- a/content/LPD422FM.rst Wed Oct 16 21:52:38 2019 +0200 +++ b/content/LPD422FM.rst Wed Oct 16 21:53:47 2019 +0200 @@ -9,7 +9,7 @@ This post is a quick presentation and teardown of a small bench power supply I bought on ebay a few weeks ago for something like 40€. -.. image:: {filename}/images/lambda/lpd422fm_overall.jpg +.. image:: {static}/images/lambda/lpd422fm_overall.jpg :alt: The Lambda LPD 422 FM dual regulated power supply. It's an old unit, not sure it's exact age, but the components inside @@ -33,28 +33,28 @@ It seems to be "remote programmable", and have remote sensor entries on the back of the unit. -.. image:: {filename}/images/lambda/lpd422fm_back.jpg +.. image:: {static}/images/lambda/lpd422fm_back.jpg :alt: Rear view of the LPD 422 FM dual regulated power supply. Inside the enclosure: -.. image:: {filename}/images/lambda/lpd422fm_top.jpg +.. image:: {static}/images/lambda/lpd422fm_top.jpg :alt: Top view of the LPD 422 FM dual regulated power supply. Each of the 2 power supplies have a regulator board on each side of the enclosure. The power transformer is sitting at the center of the enclosure and shows a nice "Component Location Diagram": -.. image:: {filename}/images/lambda/lpd422fm_xformer.jpg +.. image:: {static}/images/lambda/lpd422fm_xformer.jpg :alt: The power transformer of the LPD 422 FM dual regulated power supply. A regulator board looks like: -.. image:: {filename}/images/lambda/lpd422fm_board2.jpg +.. image:: {static}/images/lambda/lpd422fm_board2.jpg :alt: Top view of one regulator of the LPD 422 FM dual regulated power supply. -.. image:: {filename}/images/lambda/lpd422fm_board1.jpg +.. image:: {static}/images/lambda/lpd422fm_board1.jpg :alt: Bottom view of one regulator of the LPD 422 FM dual regulated power supply. @@ -70,10 +70,10 @@ ======================== - `Lambda LP, LPD & LPT series catalog - <{filename}/pdfs/lambda/LAMBDA_LPD_LPD_LPT_series.pdf>`_ + <{static}/pdfs/lambda/LAMBDA_LPD_LPD_LPT_series.pdf>`_ - `Instruction and Service Manual for Lambda LPD suffix A Series Power - Supplies <{filename}/pdfs/lambda/LambdaLPD.pdf>`_: this is not + Supplies <{static}/pdfs/lambda/LambdaLPD.pdf>`_: this is not exactly the same model, but it really very close. @@ -86,35 +86,35 @@ First, a view of the noise at the output of the PSU; 0V, no load: -.. image:: {filename}/images/lambda/DS1Z_QuickPrint2.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint2.png :alt: Noise level of the LPD422FM - 0V/0A Same at 20V, no load: -.. image:: {filename}/images/lambda/DS1Z_QuickPrint3.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint3.png :alt: Noise level of the LPD422FM - 20V/0A And at maximum voltage (40V, no load): -.. image:: {filename}/images/lambda/DS1Z_QuickPrint4.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint4.png :alt: Noise level of the LPD422FM - 40V/0A -Then, with the `ZPB30A1 electronic load <{filename}/ZPB30A1.rst>` +Then, with the `ZPB30A1 electronic load <{static}/ZPB30A1.rst>` connected but not consuming any current (20V, 0A): -.. image:: {filename}/images/lambda/DS1Z_QuickPrint5.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint5.png :alt: Noise level of the LPD422FM connected to the ZPB30A1 - 20V/0A As you can see, there is a much higher injected by the electronic load. When measuring the visible pattern: -.. image:: {filename}/images/lambda/DS1Z_QuickPrint6.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint6.png :alt: Noise level of the LPD422FM connected to the ZPB30A1 - 20V/0A it's a 20ms pattern, ie. it's the mains 50Hz being injected... Let's turn the load on (20V, 0.5A): -.. image:: {filename}/images/lambda/DS1Z_QuickPrint7.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint7.png :alt: Noise level of the LPD422FM connected to the ZPB30A1 - 20V/0.5A The injected noise from the mains has vanished, and the RMS noise @@ -122,7 +122,7 @@ At 1 amp, it's roughly the same: -.. image:: {filename}/images/lambda/DS1Z_QuickPrint8.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint8.png :alt: Noise level of the LPD422FM connected to the ZPB30A1 - 20V/1A Now, trying to capture the transient curve when activating and @@ -131,10 +131,10 @@ easier. So I've just adjusted the trigger level to single capture the moment I press the 'on/off' button of the load: -.. image:: {filename}/images/lambda/DS1Z_QuickPrint10.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint10.png :alt: Transient response of the LPD422FM connected to the ZPB30A1 - 20V/1A -> 0A -.. image:: {filename}/images/lambda/DS1Z_QuickPrint11.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint11.png :alt: Transient response of the LPD422FM connected to the ZPB30A1 - 20V/0A -> 1A The overshoot is around 75mV and takes around 200ms to vanish, and the @@ -142,7 +142,7 @@ At one amp, the ripple voltage is around 8mVpp and 3mVrms: -.. image:: {filename}/images/lambda/DS1Z_QuickPrint13.png +.. image:: {static}/images/lambda/DS1Z_QuickPrint13.png :alt: Ripple voltage of the LPD422FM connected to the ZPB30A1 - 20V/1A It's quite out of spec: ripple should be less than 500µVrms and