What can you do to distinguish constant-voltage source and constant-current source by parameter?

What can you do to distinguish constant-voltage source and constant-current source by parameter?
If you just got a led power supply . How was I to know that it’s constant-voltage source or constant-current source . first you should be find voltage Parameter from production nameplate .
The type, power and speed of the machine are seen on the nameplate. we usually go straight into analysis mode:
The specified nominal values of voltage is fix value, it is constant-voltage source an orientation position,eedle Tle along a scale.
The voltage moves a needle along a scale. it is constant-current source .