A bench DC power supply provides clean, adjustable voltage and current for testing circuits, powering prototypes, and charging batteries. Linear vs switching, single vs multi-channel, programmable vs manual — the right choice depends on what you're powering and how precise you need to be.
Linear: Heavy transformer-based. Ultra-low noise and ripple — essential for sensitive analog circuits, audio, RF. Inefficient (dumps excess as heat), heavy, larger. Switching: Lightweight, efficient, compact. More noise on output (10-50mV ripple typical vs <1mV for linear). Fine for digital circuits, motors, LEDs. Most modern programmable supplies are switching with good filtering.
Single channel: One output. Fine if you only need one voltage. Dual channel: Two independent outputs. Can be series (double voltage) or parallel (double current). Most versatile — power op-amp circuits (±12V), digital + analog rails, or two independent voltages. Triple channel: Two variable + one fixed 5V (logic). The lab standard.
Common ranges: 0-30V/0-3A (basic), 0-30V/0-5A (standard), 0-60V/0-3A (higher voltage). For most bench work, 30V/5A covers 95% of needs. If you work with automotive (12/24V systems) or power amplifiers, you may want 60V. Check if it has fine and coarse adjustment — one knob for 0-30V is frustrating to set precisely.
Manual (knobs + display): Simple, fast, always works. Programmable (USB/GPIB/LAN): Remote control, automated testing, data logging. SCPI commands. Used Keysight/Rigol/Siglent programmable supplies sell at steep discounts vs new. If you do repetitive testing, programmability pays for itself quickly.
Budget ($30-100 used): Korad KA3005D, Siglent SPD, Gophert. Fine for hobbyist digital work.
Mid-Range ($100-400 used): Rigol DP832 (3-channel, programmable), Siglent SPD3303X, older Agilent E3631A. Lab workhorses.
Precision ($400+): Keysight E36300 series, Keithley source meters. Ultra-low noise, 4-wire sensing, sub-mV accuracy.
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