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Topic: Power supply amperage?? (Read 555 times) previous topic - next topic


Alright guys, I scavenged an old Philips DVD player, and found this nifty power supply inside (photos attached).  It takes power right from the outlet, and is labelled that it has a 12v and 5v outputs.

My question is, can anyone tell me the max current I might be able to get out of this?  Or would anyone know how I can check it?  I know it works good (the DVD player was still functional) but I would hate to burn it up right away.  I have a project I am working on that uses a Nano, an ESP8266, and a 4-channel relay board, and I would much rather use this instead of two separate power supplies...


Its hard to know from just looking at the board, but from the type and size of the diodes , up to 3A would be possible.
Note that these types of power supplies need a minimum load otherwise they wont regulate properly, so if your load is a lot less than what the DVD player uses, you will need to increase the load with some resistors on the 5 and 12 v outputs.


Jun 21, 2016, 11:48 pm Last Edit: Jun 21, 2016, 11:58 pm by Transistors
The datasheet for one of the chips ( http://dalincom.ru/datasheet/TNY176PN.pdf ) (On the top of page 9 says this:

output power product

 230 VAC ±15%                        |        85-265 VAC
    11.8         15.3        19.4           |    9.2           11.9        15.1


Aug 29, 2016, 09:37 pm Last Edit: Aug 29, 2016, 09:38 pm by mrburnette
nd is labelled that it has a 12v and 5v outputs.
On the rear of the DVD player is a label that has the AC input value and should have the AC amps as well as the power dissipation in total Watts.  The total Watts is the manufacturer's rating that includes the working curent * working voltages and the power wasted as heat from the inefficiency in the system.

In a perfect world, 120 Volt in at 500mA would provide 12 Volts at 5 Amps.  Notice that the Watts on both side of the power supply equal.  There is not enough information in your post to know the 12V / 5V individual ratings.

You should have no problems using that supply with an Arduino/ESP8266 project unless you start driving strings of LEDs or big servo motors.



It looks like the +5V has the higher current
( by my guess of 2 output leads ).
If I wanted to test it, I'd attach a thermal couple
to the transistor below the transformer. This
is the switcher.
Watch the temperature of that transistor.
Be especially careful. The input switcher usually
runs at 250V DC with enough current to kill.
Don't even think of using your finger to test
for temperature.


hello !
i have a problem with powering 5 servo motors. i powered them on 5 voltage and 3.5amp but they are getting hot so fast. what power should i apply.thanks before

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