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How to test DC adapter for reliability and performance?
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Surajg:
Hello Everyone,

I am newbie to electronics. Please forgive me if I have posted it in incorrect forum  :)
Recently I purchased some 12V-2.0A DC adapters from market.

I did check the voltage on multimeter and its output is OK as mentioned.
I was wondering how to test any adapter for reliability or other issues (like noise etc using oscilloscope or any other instrument) if we are planning to use it for mass production.

Thanks
Zero999:
Where did you buy it from and what's the brand?

If you're going to buy a large quantity, then you could get a hi-pot. tester to check the insulation between primary and secondary. Such a test is normally destructive, or at least weakens the insulation, so the device mustn't be used afterwards. You could also open it up and visually inspect it. What brand and temperature rating capacitors does it use? Are the creepage distances on the PCB sufficient? Does the transformer have sufficient separation? Does it have EMI suppression i.e. a common mode choke and Y capacitor?
duckduck:
Depending on the expected use, it might make sense to verify that the DC adapters meet their spec of 12V@2A. This could be done by hooking it up to a DC electronic load (or a very robust 6 Ohm resistor) and then monitoring the temperature of the adapter to make sure that it doesn't get too hot after several hours. The voltage could also be monitored at full (2A) load for several hours to make sure that it stays high enough to meet your specifications. You could even do this testing at depressed or elevated ambient temperatures (e.g. 0° C or 45° C). It's really up to you to define what your requirements are.

EDIT:

You could watch the voltage on an oscilloscope to see how much electrical noise there is, but unless you know the requirements/sensitivity to noise of the device that you are powering this is not very helpful.

Probably the most important thing is that you know the range of voltages (and power consumption) that your device operates reliably within e.g. 11.5V - 13.7V, and then ensure that the DC adapters will provide this output with a nice margin under all circumstances that you expect your device to see in the field.

You can also use a variac to ensure that the DC adapter puts out the rated voltage / amperage at whatever the range of voltages are for the countries that you wish to sell your device in e.g. 240V +/- 5V.
Gyro:
If you are planning to use the adapters for mass production, then you are effectively taking over approvals and safety responsibility for them as they will be shipping inside your product's retail packaging.

In additional to the destructive testing that Zero999 suggests, you need to obtain full EMC and Safety approvals documentation from the manufacturer and ensure that it is honest and correct for your market (consumer, IT etc). Once you are in mass production, responsibility for them becomes yours and the adapter manufacturer, your subcontractor. You need full approval documentation to demonstrate that you undertook due diligence if the worst happens.
wraper:

--- Quote from: Zero999 on July 30, 2021, 09:35:22 am ---Where did you buy it from and what's the brand?

If you're going to buy a large quantity, then you could get a hi-pot. tester to check the insulation between primary and secondary. Such a test is normally distructive, or at least weakens the insulation, so the device mustn't be used afterwards. You could also open it up and visually inspect it. What brand and temperature rating capacitors does it use? Are the creepage distances on the PCB sufficient? Does the transformer have sufficient separation? Does it have EMI supression i.e. a common mode chock and Y capacitor?

--- End quote ---
It's only destructive if you test a breakdown voltage. Hi-pot test is not destructive because a limited voltage is applied which insulation must withstand and every device like PSU must be tested at factory if things are done right.
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