Alternating Current Adapter; when plugged to AC Power (usually 117VAC/60Hz in the United States)
it produces 12VDC, 24VAC or others.
“UL Listed”or ” Regulated ” recommended. It also called Power Transformer.
Phase Alternating Line system
A color television system, which is used in Europe, Australia , parts of Africa and the Middle East .
It has 625 horizontal
scan lines and 25 frames per second.
National Television System Committee; formulates standards for American color television system.
NTSC system has 525 horizontal scan lines and 30 frames per second.
Alternating Current Power
In the United States, the standard AC Power is single-phase 117VAC/60Hz and is provided from power
outlets in the house. 24V AC power can be produced from an AC Adapter.
Direct Current Power
Can be derived from an AC adapter or from a battery. Among DC voltages of 6, 9, 12, 24, and 28,
12V DC is most common in the CCTV industry.
CCD (charge coupled device)
Consists of several hundred thousand individual picture elements (pixels)
on a tiny 1/2″, 1/3″ or 1/4″chip.
Each pixel responds to light falling on it by storing a tiny charge of electricity.
The pixels are arranged on a precise grid,
with vertical and horizontal transfer registers carrying the signals to the camera’s video processing circuitry.
This transfer of signals occurs sixty times per second.
The 1/3″CCD chip is the most widely used sensor format these days;
its size is 5.5mm (diagonal), 4.4mm (horizontal) and 3.3mm (vertical).
The 1/4″ sensor format, recently being used in color cameras,
is 4mm (diagonal), 3.2mm (horizontal) and 2.4mm (vertical).
A part of the CCTV system that receives the video picture from a camera and displays them
B/W Monitor and Color Monitor
In the past, 9 to 12 inch (diagonal) B/W monitors were widely used in the field.
These days, many people are looking for 14 inches for color monitor
and 17 inches for B/W.
As the color monitor needs 3 different color dots to produce one pixel of
information on the monitor, it usually has lower resolution than B/W monitor.
Single Monitor, Quad Monitor and 4-CH. Monitor
Single Monitor is usually professional monitor with one video input of BNC jack.
Quad splitter, video switcher or multiplexer
can be connected to single monitor to combine multiple cameras.
Quad monitor has built-in quad splitter and usually has 4 DIN
jacks for video inputs.
4-CH Monitor has built-in 4 channel video switcher and usually
has 4 DIN jacks for video inputs. Quad Monitor or 4CH.
Monitor is usually a part of packaged observation system and
is not compatible with other Manufacturerr’s camera or cable.
About two thirds of the professional cameras work with 24VAC, 20VA to 40VA.
The cameras usually have screw type connections
and you don’t need to worry about the polarity.
This power is usually supplied with AC Adapter and you need to prepare
separate power cable for the connection.
Unlike 12VDC, this power can be transmitted to a long distance up to 450ft and is
proper for the cameras that are to be installed out-door or
when you don’t have the power outlet near the camera.
Most board cameras, mini cameras and about one third of the professional cameras work with 12V DC,
100mA to 200mA for B/W cameras and 150mA to 300mA for color ones.
These cameras usually have DC jacks to accept DC power plugs.
You should be careful about the polarity (positive and negative) for this power source.
12V DC power can be supplied with AC Adapter or battery pack.
You may even use a “power cord” plugged to the cigarette lighter in a car.
Digital Video Recorder records video pictures digitally. DVR
Digital Video Recorder, records video pictures digitally on a
hard disk drive(HDD). This HDD, usually built-in, has capacity of 20 Gb, 30 Gb or 60Gb to store the records.
You can program the picture resolution and recording time according to the application;
real-time or time-lapse recording also available.
Overwriting the oldest pictures is programmable.
Event alarm recording that records, only when a movement is captured within
the image frame, is easier to program and more reliable
than the Time Lapse VCR’s alarm recording function.
You just assign dots over the screen where you want to detect the movement.
As DVR records digitally, the image quality remains the same
regardless of how many times the images are stored or rerecorded.
And, you can select images quickly by using time/date or
alarm search, or just browsing through.