DC Power Supply: Siglent SPD3303C

By Lab Technical Team

    Resources

    Understanding Constant Voltage (CV) vs. Constant Current (CC)

    The Siglent SPD3303C is a high-precision, linear triple-output DC power supply featuring two adjustable channels (CH1/CH2: 0–32 V / 0–3.2 A) and one selectable fixed channel (CH3: 2.5 V, 3.3 V, 5.0 V / 3.2 A).

    Operating ModeIndicator LightBehavior
    Constant Voltage (CV)Green LEDThe supply maintains your target voltage setting. Current varies automatically based on the load resistance ($I = V/R$).
    Constant Current (CC)Red LEDThe circuit attempts to draw more current than your current limit setting. The supply clamps the output voltage downward to enforce the current ceiling.

    Safety Warning: Always turn off or disable the output before connecting or modifying your breadboard wiring. Applying power to miswired components can cause immediate damage.

    Basic Independent Channel Setup

    1. Power On: Flip the rocker switch on the lower-left corner to turn on the supply.

    2. Disable Output: Ensure the green ON/OFF button is OFF (unlit) while setting parameters.

    3. Select Channel: Press the CH1 or CH2 button on the panel to bring up its active parameter cursor on the digital screen.

    4. Set Target Voltage:

      • Press the Voltage button.
      • Turn the rotary knob to adjust the voltage level (or press the knob inward to toggle digit selection for coarse/fine tuning).

    5. Set Current Limit (Safety Ceiling):

      • Press the Current button.
      • Turn the rotary knob to set a safe upper threshold (e.g., 100 mA or 0.100 A for standard low-power logic circuits).

    6. Connect Leads: Connect banana plug leads from the Red (+) and Black (-) terminals of CH1 directly to your breadboard power rails.

    7. Enable Output: Press the ON/OFF button so it lights up green.

    8. Verify Mode: Check the channel LED indicator next to the output terminals:

      • Green LED (CV): Your circuit is drawing less than the current limit; the set voltage is being delivered.
      • Red LED (CC): A short circuit or excessive load exists. Turn off the output immediately and inspect your breadboard.

    Operating Tracking Modes (Series & Parallel)

    The SPD3303C includes internal relay switches to combine Channel 1 and Channel 2 internally without requiring external jumper wiring between terminals.

    ModeButtons / SelectionTotal Output CapabilityTerminal Connections
    IndependentDefault ModeCH1: 0–32V / 3.2A
    CH2: 0–32V / 3.2A    		Use individual CH1 and CH2 terminal pairs separately.
    SeriesPress Series mode button0–64 V @ 3.2 AConnect load across CH1 Red (+) and CH2 Black (-).
    ParallelPress Parallel mode button0–32 V @ 6.4 AConnect load across CH1 Red (+) and CH1 Black (-).

    Using the Fixed Auxiliary Output

    Channel 3 provides a clean, fixed voltage source ideal for powering digital microcontrollers and logic ICs.

    1. Locate the CH3 terminal block on the right side of the front panel.
    2. Press the 2.5V / 3.3V / 5.0V softkey toggle switch until the indicator LED corresponding to your target logic voltage (e.g., 5.0V) lights up.
    3. Connect your breadboard leads to the CH3 (+) and CH3 (-) terminals.