OPERATIONS
Basic Mode of Operation
This power supply is designed to operate as a constant voltage source or as a constant current source. Automatic
crossover to either mode of operation occurs when the load condition changes as following:
Constant Voltage (CV), Automatic crossover & Constant Current (CC)
The power supply functions as a constant voltage source (CV) as long as the load current is less than the preset
current limiting value. When the load current is equal to or greater than the preset current limiting value, the power
supply will automatically cross over to the constant current mode, voltage will drop, (CC) will show on the LCD
display panel and it will operate as a constant current source.
When the load current drops below the preset current limiting value, the supply returns to constant voltage (CV)
mode.
Set the Output Voltage and Presetting Current Limiting Value (CC)
Turning the voltage or current knob to set your desired values.
Quick pushes on the knobs will move the decimal place for fast tuning.
Turn the knob when the desired number column is flashing otherwise you need to repeat quick pushes again.
One quick push on the current knob to see the preset current limiting value.
Aux. output 1 voltage selection
Move the switch (4) at the back of power supply for selection of 3.3 or 5 VDC.
At 3.3VDC setting, indicator (15) is Off
and at 5VDC setting indicator (15) is On.
Connection and Operation Procedure
1. Check the rating label and plug in to AC mains.
2. Switch on the power supply and the LCD display should be on at the same time.
3. The (CV) icon should be shown on the display.
4. Turn to current volume knob (6) to maximum clockwise if you do not require lower Current limiting value,
otherwise do the preset the (CC) limiting procedure.
5. Set your desired output voltage and then turn off the output terminal by push button (7).
6. Connect to your load positive to positive and negative to negative.
7. Turn on the output terminal again and check if display shows (CV).
8. If display shows (CC), either your preset current limiting value is too low or your load requires more voltage and
current. You need to re-access the voltage and current requirement of your load and increase the voltage or
current accordingly until (CV) appears.
Connecting the 3 outputs
(using NTP -5531, 1-36V, 0.25-3A as an example)
All the three outputs are fully isolated from ground and with each other so that it is possible to make cross
connections to power a circuit board or device that requires for example: +3 or +5V, +12 V or -12V and 1-36V as
shown in Fig.1.
The variable main output is set for 12V and it is assigned as the +12V source (available maximum current 3A)
Note the variable main output can be set for other voltage (1-36V) such as 16V.
The fixed 12V is made as the - 12V source.
The fixed 5V is made as the +5V source.
