Every bench power supply and electronic load gets a score from 0 to 100% built from six factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Products are grouped into single-output supplies, multi-output supplies and electronic loads, and use the same scale in every group.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per rated watt | 25% |
| Output quality | ripple and noise for a supply; dynamic-mode frequency for a load | 20% |
| Resolution | voltage and current setting steps | 15% |
| PC control | PC interface, LAN and SCPI commands | 15% |
| Protection & features | over-voltage and over-current protection, remote sense, stored setups | 10% |
| Warranty | warranty length | 15% |
Where the numbers come from
Ratings, ripple and noise, resolution, interfaces, protection and warranty come from the maker’s datasheet, manual or product page, including the maker’s own copy on a retail listing. Where two of the maker’s own figures conflict, the value is left out rather than guessed. Prices are checked at the stores the page links to, and the lowest is used.
The factors
Value is the current price divided by the rated power, in dollars per watt, on a log scale, so halving the price always counts the same. $5 per watt scores zero and $0.15 per watt full marks. Rated power is the maker’s total output rating, or an electronic load’s rated input power. Where a maker gives no total, the published channel ratings (volts times amps for each channel) are added up, and the product page says so.
Output quality means different things for the two kinds of product. For a power supply it is the published constant-voltage ripple and noise, on a log scale: 20 mVrms scores zero and 0.3 mVrms full marks. When a maker publishes only a peak-to-peak figure, 200 mVp-p scores zero and 2 mVp-p full marks. For an electronic load it is the fastest dynamic (transient) mode frequency: 1 kHz scores zero and 30 kHz full marks.
Resolution is the smallest voltage and current step you can set, on a log scale, averaged across the two: 100 mV scores zero and 1 mV full marks for voltage; 10 mA scores zero and 0.1 mA full marks for current. Where a maker publishes only the meter (readback) resolution, that is used.
PC control is 50% for a PC interface (USB, RS232, RS485, LAN or GPIB), 20% for LAN and 30% for documented SCPI commands. An analog remote terminal doesn’t count as a PC interface.
Protection and features is 30% for over-voltage protection, 30% for over-current protection, 20% for remote sense and 20% for stored setups.
Warranty is the maker’s warranty: 1 year scores zero and 3 years full marks.
What isn’t scored
Maximum voltage and current, the number of channels, linear or switching regulation, weight, load modes and release date are listed but not scored. Voltage and current decide which supply fits a job more than which is better, so they are left to you.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. PC control scores neutral only when the maker says nothing about interfaces, and protection and features only when none of them is published; a feature the maker doesn’t mention otherwise counts as absent. There are two exceptions. A maker that doesn’t publish a warranty gets no warranty counted, so that factor scores zero, the same as a one-year warranty. A power supply whose maker doesn’t publish ripple and noise also scores zero on output quality, since a neutral score would rank it above supplies that publish a respectable figure. Both are marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.