It depends on your application. For precision applications, linear supplies are heavy, hot, and expensive—but worth it if you need <350μVrms noise or <50μs transient recovery. For general lab use, modern switching supplies offer better value[1].
[FIG 3.1] TOPOLOGY NOISE PROFILE
01.The Trade-off
Linear (Series Pass)
- ✓ Zero Switching Noise
- ✓ Ultra-fast Transient Response
- ✗ Heavy (Transformer based)
- ✗ Low Efficiency (40-60%)
Switching (SMPS)
- ✓ Compact & Lightweight
- ✓ High Efficiency (>85%)
- ✗ Higher PARD
- ✗ Slower Loop Response
02.The Great Inversion
There is a paradox in power engineering: The older the technology, the higher the precision status.
Switching supplies are modern marvels—light, efficient (90%+), and cheap. But they are inherently "dirty" due to high-frequency switching noise. Linear supplies are the dinosaurs—heavy transformers, hot heatsinks, and 50% efficiency. Yet, for a High Precision DC Power Supply, this "inefficiency" is the price of perfection. The linear topology offers a physically quiet output that no amount of digital filtering can fully match in precision applications.
For loads >1kW, demanding "Linear-level noise" is physically impractical. In high-power applications, engineers trade noise floor for Recovery Time and Stability.
Buy a Linear Supply ONLY if:
- You are characterizing low-level analog circuits (Audio, Sensors).
- You require <50μs transient recovery.
- You are working in a shielded RF environment.
Otherwise, save your money (and desk space) and buy a high-quality Switching supply.
Related Analysis
References
[1] Wikipedia: Linear Regulator - Technical background on linear power supply topologies