1.Strong Research & Develop team;
2. OEM and ODM are Acceptable
3.With excellent sales team,and professional service
4.With kinds of personal mobile alarm products which can be met clients needs
5.Manufacturer to produce personal mobile alarm products ;
1.With DHL,UPS and Fedex shipping methods for shipping the product ;
2.Competitive price, No MOQ, Fast delivery (within 5 days);
3.Stable quality,can be provided such as CE, FCC,ROHS certifications
4.Products all tested from semi-finished product to pre-packing.
5.Strong designer team for free to provide the products of high-resolution pictures, advertising page, or catalogs;
6.Warranty service: six month for return(except man-made problem),one year for repair
Alternating Current Power. In U.S.A, the standard AC Power which is single-phase 117VAC/60Hz and is provided from power outlets at house. 24V AC power can be produced from the AC Adapter.
Alternating Current Adapter; when it is plugged to AC Power (usually 117VAC/60Hz in the United States)
it produce DC12V, AC24V or others. "UL Listed" and "Regulated" recommended. which is also called Power Transformer.
Most cameras, DVR cameras and about one third of the cameras work with DC12V 100mA to 200mA for B/W cameras
and 150mA to 300mA to color ones.
About two thirds of the cameras work with AC24V, 20VA to 40VA. The cameras have screw type connections
and you don't need to worry about the polarity.
This power is usually provided with AC Adapter
and you need to be prepare separate power cable with the connection. not like12VDC,
this power can transmitt to a long distance up to 450ft and is proper for the cameras that are to be installed out-door
or when you do not have the power outlet near the camera.
The video signal is amplified at low light levels by the automatic gain control circuit.
Unfortunately noise is also amplified. In some cameras the gain level can be controlled manually.
(MGC = manual gain control).
The number of hertz (cycles per second) displaying the difference between the lower
and upper frequencies of a frequency band video uses higher frequency than audio, thus needs a wider bandwidth.
ANGLE OF VIEW
The scene angle that a video camera lens can show on the monitor,which is like Diagonal Angle,
Horizontal Angle and Vertical Angle, usually described in degree.
Focal Length (FL) which is the distance from the center of a lens to the focal point (CCD sensor chip). FL,
as well as the CCD chip's format, it is the major elements to determine the angle of view of a lens.
Such as, a 6.0mm FL lens on 1/3" sensor format has 56.8 degrees of diagonal angle of view
and a 5.0mm FL lens on 1/3" sensor format has 66.9 degrees.
Well, the same 6.0mm FL lens can see 75.5 degree on 1/2" sensor format.
The angle of view also varies a little depending on the Manufacturer of the lens.
For 1/3" CCD chip camera, the following formula which is an easy way to determine the focal length of a lens needed.
(Distance to subject / Width of subject) x 4.5mm = Focal Length.
Such as, if you want to see a subject of 5.5ft width at 10ft distance with a 1/3" CCD camera,
you will need a 8.0mm FL lens. which is, 10ft / 5.5ft x 4.5mm = 8.18mm.
A 8.0mm FL lens mounted on 1/3" CCD camera will cover the subject you want to see.
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