1. Constant current: no matter how the load changes, the output current remains unchanged. If the ammeter is connected to the load in series and the voltmeter is connected in parallel, it will be found that the larger the internal resistance of the load is, the higher the output voltage is, and the ammeter indication remains unchanged.

2. Constant voltage: it is what we often call regulated power supply. For example，24v led power supply and mini 12v led power supply is common. No matter how the load changes, the output voltage remains unchanged. If the ammeter is connected to the load in series and the voltmeter is connected in parallel, it will be found that the larger the internal resistance of the load is, the smaller the output current is, and the indication of the voltmeter remains unchanged.

Note: all the above are ideal constant voltage constant current driver led

1. The actual constant current power supply is limited in the range of output voltage (power range). If the output voltage is lower than the lower limit or higher than the upper limit due to the change of load, the power supply will automatically protect or stop the output and give an alarm.

2. The actual constant voltage power supply is limited by the output current range (power range). If the output current is higher than the rated value due to the load change, the power supply will automatically protect or stop the output and give an alarm.