Author Topic: CCTV cameras - Powering them from the PC?  (Read 2022 times)

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Offline cs.dkTopic starter

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CCTV cameras - Powering them from the PC?
« on: August 16, 2015, 10:12:25 am »
As subject.
Is it safe to power CCTV cameras from the PC's PSU? I think the outer of the BNC is grounded to the chassis/earth. But is the negative of the PSU grounded to, or will something bad happen? I may just try to measure the negative rail with respect to ground?
The cameras consume 200 mA (with IR leds on, IIRC) so the load isn't that big.

 

Offline fcb

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Re: CCTV cameras - Powering them from the PC?
« Reply #1 on: August 16, 2015, 10:19:55 am »
You might get ground-loops and noise. It's very likely that the BNC outer and the cameras 0V are the same.

Also,if the cameras are exterior you should think about things like lightning strikes and EMC.
https://electron.plus Power Analysers, VI Signature Testers, Voltage References, Picoammeters, Curve Tracers.
 

Offline cs.dkTopic starter

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Re: CCTV cameras - Powering them from the PC?
« Reply #2 on: August 16, 2015, 10:29:41 am »
Thanks,
The cameras will be outdoors.. I better find a suitable plugpack for them.
 

Offline drcheap

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Re: CCTV cameras - Powering them from the PC?
« Reply #3 on: August 17, 2015, 06:32:56 am »
FWIW, IP cameras with PoE support make this sort of thing a non-issue.

But if you've already got the oldschool cameras that may not be an option.
 

Offline Richard Crowley

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Re: CCTV cameras - Powering them from the PC?
« Reply #4 on: August 17, 2015, 06:36:45 am »
Yes it is typically safe because the signal ground (the outer ring of the BNC/RCA/whatever connector is circuit ground. And all the power busses in the computer are referenced to that same circuit ground.

At 200mA each, I agree that isn't much of a load so chances seem pretty good that a typical computer power supply would have sufficient surplus power.
 

Offline cs.dkTopic starter

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Re: CCTV cameras - Powering them from the PC?
« Reply #5 on: August 17, 2015, 12:27:45 pm »
Well i've got 4 cameras and pc, software and a monitor for free. I did find a 12V 2A supply in my parts bin yesterday, so they're up running :)

It's some Linux software I think, the PC can boot without HDD, so the OS may be in a ROM?
 


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