Every programmable DC electronic load does fundamentally the same job — sinking current from a device under test and absorbing the power that represents. What happens to that absorbed power once it's inside the load is where the genuinely consequential design choice lies: dissipated as heat (resistive/dissipative load), or converted and fed back into the supply grid (regenerative load).
How the Two Architectures Actually Work
Dissipative (resistive) electronic loads absorb power and convert it entirely to heat via heatsinks and cooling. The ActionPower ATLAS series uses this approach, delivering 2kW per 3U module scaling to 60kW per rack and 600kW with parallel expansion, with current response as fast as 20μs.
Regenerative electronic loads convert absorbed power back to usable AC power fed into the building's electrical supply. The ActionPower PRL series achieves up to 85% regenerative efficiency at steady state.
Why Regenerative Efficiency Matters Beyond the Electricity Bill
Cooling infrastructure scales with dissipated power, not absorbed power. A 600kW dissipative load array needs cooling sized for 600kW of waste heat. The equivalent regenerative system at 85% efficiency only needs cooling for the remaining 15% — roughly 90kW.
This becomes the limiting factor in high-power, high-duty-cycle applications — AI data centre power supply validation and large-scale battery pack testing are exactly where the thermal difference determines whether a facility can support the test program without a major cooling upgrade.
When Dissipative Loads Are Still the Right Choice
- Lower power, intermittent-duty applications where the difference is too small to justify added complexity
- Applications prioritising maximum measurement accuracy — the ATLAS series specifies voltage measurement accuracy of ±(0.025%+0.025% F.S.) and 16-bit current resolution
- Facilities where grid feedback isn't straightforward — some facilities face genuine technical or compliance hurdles feeding regenerated power back to the grid
Dynamic Response — A Separate Axis From Regeneration
"Regenerative vs dissipative" and "fast vs slow dynamic response" are two genuinely separate design axes. The PRL series combines a peak current slew rate up to 60 A/μs and minimum rise time as fast as 6μs with up to 85% regenerative efficiency in the same unit — purpose-built for AI data centre power infrastructure validation.
Matching Load Architecture to Application
| Application | Primary requirement | Better fit |
|---|---|---|
| AI data centre PSU/PDU validation | Extreme dynamic response + sustained high power | PRL regenerative |
| Battery pack cycle life testing | Sustained power, thermal/cost matters | Regenerative |
| General production-line power supply test | Standard load profile | ATLAS dissipative |
| Precision measurement / calibration | Maximum accuracy, lower power | ATLAS dissipative |
Practical Specification Checklist
1. Calculate total power and expected duty cycle over the realistic lifetime of the program.
2. Confirm facility capability for grid feedback if considering regeneration.
3. Separately evaluate dynamic response requirements against your test profile.
4. For sustained high-power applications, model the actual cooling infrastructure cost difference.
5. Confirm measurement accuracy meets precision requirements, independent of architecture type.