Malfunctioning of a Power Supply 5V-5A

Gee, a valid question, yet it gets marked off topic and immediately a whole bunch a people blindly jump in to offer help. :-)

receptacles are cheap

I would suggest a separate ups for this equipment, with pure sine wave output...

http://www.minutemanups.com/support/pwr_un10.php

...I also would make sure this is an approved use of this technology...

http://propakistani.pk/2012/05/07/pta-warns-to-dismantle-illegal-mobile-phone-jammers/

Do you have any more information on how the power supply has failed - primary side, secondary side, etc? Could it be high harmonic content from the UPS? What's on the 'scope trace by the way?

My guess is that your friend keeps using a SMPS (Switch Mode Power Supply) and the lousy waveform from the UPS causes dv/dt spikes that quickly destroy the input capacitor. Try using an older transformer based power adapter, or buy a professional AC-DC bench power supply that has some descent filtering on both the line and output side.

Cheapest way would be to run the 5V PSU directly from the mains, unless the power fails, when it could be manually connected to the UPS for the duration of the power-outage. After all, how much illicit mobile phone use would there be before someone noticed the power failure and switched over ?

Cudo's for RamConsultant. The harmonics in a non-sinusoidal supply will cause problems in other ac to dc supplies. A very simple solution would be to buy an isolation transformer between 0.5 and 1 KVA. It will throw off a lot of the nasties in the form of heat, but that much mass of iron should be sufficient to protect the little DC supply.

I have to question the wisdom of having a phone jammer running on a UPS. If you have an emergency in a power failure, what do you plan to do? Perhaps someone will get a blanket and send smoke signals?

I agree that an isolation transformer will likely resolve this problem, but I think that the transition to and from UPS operation is likely the root culprit and not the harmonic content.

As for the legality and safety issue, this is in Pakistan. A cell phone jammer maybe a legal, safety requirement.

Thanks to all for their feed back.

I think an isolation transformer based power supply is possible for me to arrange and according to the members, the problem will be eliminated by using it.

Is the CRO photo a shot of the input voltage? If it is then there is a lot of clipping, this will cause quite a lot of power supply radiation - as opposed to the radiation of your jammer -. This could be quite dangerous and should be addressed quickly.

What are you smoking?

Something better than What you are..

Study power line radiation, see the harmonics radiated by clipping and therefore the radiated rubbish from such clipping.

Since the author has mentioned that this is the output of the device, my original comment is now a moot point.

Peace dude!

The wave form is not clipped. It is generated, by design, to be that shape.

Clipping is a form of distortion. Distortion is unintended alteration. Nothing unintended here.

Modified sin wave has gone out of vogue (almost) because of the harmonics that these things vomit. Other reasons too.

Sorry my response was taken with so much agony mate.

You reckon your smoke is better than mine do you? Worth exploring.

"It is generated, by design, to be that shape." - they'd much rather generate sine waves, but the waveform shown is easier and cheaper to produce.

Exactly.

Hi Jacko the Aus;

Yes the image of CRO is of input voltage. But this is the standard out put wave form of this UPS i.e. not a pure sine wave type.

Modified sin wave UPS...very last century.

Just get a a pure sin wave online UPS and be done with it. Cheaper than a decent jammer.

Have you tried using an SMPS type power supply. To me, it appears that u are using a linear PSU.

Gajanan Phadte

http://www.analogti.com/thermo-system-components/high-efficiency-tec-controllers.html