During voltage adjustment, it was found that the no-load voltage could not be increased.
Operators sometimes prefer to turn the "current adjustment" potentiometer all the way to the left, resulting in the inability to adjust the unloaded voltage of the power supply. This indicates a lack of substantial understanding of "current adjustment." Since the power supply still consumes a tiny amount of current even when unloaded, turning "current adjustment" to zero prevents even the smallest current from flowing, thus the unloaded voltage cannot be increased. Therefore, it is generally advisable not to turn "current adjustment" all the way to zero (turning it to about a quarter of a turn to the right should prevent the aforementioned issue).
Standard Operating Procedure: When setting the output voltage of a stable voltage power supply, turn the current adjustment knob clockwise to the bottom and hold it. Adjust the voltage control knob to control the output DC voltage value. When using the stable current source to output current, turn the voltage control knob clockwise to the bottom and hold it, then adjust the current control knob to control the output DC current value.
II. Output with voltage but no current, or with current but no voltage
In any of the aforementioned scenarios, the power supply operates normally. Operators should check that their loads are properly connected, are not experiencing short circuits or open circuits, and are in compliance with standards. In extreme cases, if the power supply has a voltage output (constant voltage state) and the load wire is broken, the output current will naturally be zero. Similarly, if the power supply has a current output (constant current state) and the load is short-circuited, the output voltage will naturally be zero.
The power supply has both voltage and current outputs, but when trying to adjust the voltage, it can't be increased anymore, or when the power supply has voltage and current outputs, and you try to increase the current further, it can't be amplified much more.
This is due to the operator's lack of clarity regarding the "constant pressure" and "constant current" concepts. If the "constant pressure" light is on, it indicates that the power supply is operating in a constant pressure state (where voltage is considered to be the dominant factor). At this point, the output current's magnitude is determined by the load, not by the operator's adjustment – meaning the current is in a passive role. If the right旋 "current adjustment" knob is turned, the current will not increase. However, if the right旋 "voltage adjustment" knob is turned, the output voltage will rise, and so will the output current, with voltage being the primary factor and current following suit).
Similarly, if the "constant current" light is on, it indicates that the power supply is operating in constant current mode. In this case, the output voltage is not adjusted in but determined by the load. Only by adjusting the "current adjustment" knob will the output current change, and the output voltage will vary accordingly.
