| Quantity | How to measure | Typical target/notes | |---|---:|---| | Output ripple | Oscilloscope across output cap, use AC coupling | <50 mVpp for low-noise supplies | | Efficiency | Pout / Pin = (Vout×Iout)/(Vin×Iin) | >85% for modern buck at medium loads | | Temperature | IR thermometer or thermocouple on case | Keep junction < 125°C (device-specific) | | Transient response | Step load change with electronic load; measure overshoot/time | 10–100 μs recovery desirable |