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12V DC CAMERA POWER SUPPLIES
The principles for selection of a 12V DC power supply are similar to those for 24V AC units. Use the table on page 9
to help you choose the appropriate power supply for your needs. The main selection criteria are
• The number of cameras to be powered
• The current draw.
In figuring the current draw remember that the total power available is not the sum of the maximum available from
each of the outputs. For example, the PS-1280DC has 8 outputs and you may draw up to 1.1 Amps from any output.
However, your total current (obtained by adding the draw of all the cameras) should not exceed the total available
current of 2.5 Amps. Loading each output at 1.1 Amps for a total of 8.8 Amps would clearly overload the supply!
• As a safety measure, we recommend running a power supply at or below about 75% of its total power for
continuous operation. This allows for fluctuations and provides a more reliable installation.
• With DC power supplies, it is very important to observe polarity. Make sure + is connected to + and - to - .
• Some examples of voltage drop are shown in the following tables. Notice the effect of the cable gauge. Using 18
AWG (American Wire Gauge) cable reduces the voltage drop dramatically over the thinner 22 AWG.
24V AC CAMERA POWER SUPPLIES
As a safety measure, we recommend running a power supply at or below about 75% of its total power for continuous
operation. This allows f or fluctuations and provides a more reliable installation.
With longer cable runs, it is important to calculate the likely voltage drop which will occur. Stealth provides a handy
software program called Stealth-Calc to help you do this. Some Call or email us for your copy. Some examples of volt-
age drop are shown in the following tables.
• Notice the effect of the cable gauge. Using 18 AWG (American Wire Gauge) cable reduces the voltage drop dra-
matically over the thinner 22 AWG.
• Another way to overcome the effect of voltage drop is to use a 28V AC power supply. Starting out with 4 more ex-
tra volts translates directly to having 4 extra volts available at the camera. See the example below.