Dennis Frie

- a couple of projects and pictures


(2010) Velleman PSS4005 lab power supply (measurements)

While looking for a new power supply, Velleman PSS4005 laboratory power supply, caught my attention.
The price was a bit high compared to similiar power supplies, but the the performance and features looked promising at the paper. Unfortunatly, I was a bit disappointed with the actual performance. A quick test quickly revealed, that especially the current-limit didn't work very well.

At first test, the following was used:
Limit: 0,06 A
Load: 56 ohm

When output is turned on, an output-voltage at 40 volt is present. The power-supply seems to measure the output-current (with quite a bit of delay), and decides to turn off the output, as the current-limit have been exceeded. When the output have been turned off the current limit is no longer exceeded and it turns the output on again, exceeding the current-limit quite a bit again. The picture shows it pretty well.

Top 40 volt (0,7 A = 1190% higher current than the preset limit)
"Oscillations" after turn on, 0-9,7 volt (0,17 A = 283 % higher than limit)
When output is turned on:

Can not show picture

- and the oscillations after the output have been turned on:

Can not show picture

Using the power-supply to drive a LED or similiar using the current-limit will quickly toast the LED (tried that as well).
If I needed a frequency-generator, I would have bought that and not a power-supply.

The power supply was returned to the supplier without problems.

All in all, if you need a power-supply, I can't recommend this one.