Why can't the current be adjusted up or the voltage not be adjusted up when using a DC stabilized power supply?
Phenomenon 1: The output has voltage but no current, or has current but no voltage
Regardless of the above situation, the power supply is working normally, and the operator should check whether the load is in good contact, whether the load is short-circuited or open, whether the load meets the specifications, and so on. In extreme cases, if the power supply has a voltage output (constant voltage state), and the load line is disconnected, the natural output current is equal to zero. Similarly, if the power supply has current output (constant current state), and the load is short-circuited, the natural output voltage is equal to zero.
Phenomenon 2: When adjusting the voltage, it is found that the no-load voltage cannot be adjusted up.
Some operators like to turn the "current adjustment" potentiometer all the way to the left, so that the no-load voltage of the power supply cannot be adjusted. This shows his lack of substantial understanding of "current regulation". Because the power supply consumes a little current even if it is no-load, and if you turn off the "current regulation" to zero, even a small current will not be released, and of course the no-load voltage will not rise. Therefore, the "current regulation" is generally not adjusted to zero (the above situation will not occur if it is adjusted to the right about a quarter turn).
General operation method: When the output voltage of the regulated source is used, the current adjustment knob should be turned clockwise to the end and kept. Adjust the voltage adjustment knob to control the output DC voltage value. When outputting current as a steady current source, turn the voltage adjustment knob clockwise to the end and keep it. Adjust the current adjustment knob to control the output DC current value.
Phenomenon 3: The power supply has both voltage output and current output, but if the voltage is adjusted again, the voltage cannot be adjusted up. Or the power supply has voltage output and current output. If you want to increase the current, the current will not be adjusted much.
This is because the operator is not clear about the concepts of "constant voltage" and "constant current". If the "constant voltage" light is on, it means that the power supply is working in a constant voltage state (it can be considered that the voltage is in the active position), and the output current at this time is determined by the load, not by the operator (it can be said that the current is Passive status), if you turn the "Current Adjustment" knob to the right at this time, the current will not increase. But at this time, turn the "Voltage Adjustment" knob to the right, the output voltage will increase, and the output current will also increase accordingly. (Voltage is master, current is slave).
Similarly, if the "constant current" light is on, it means that the power supply is working in a constant current state, and the output voltage at this time is not "adjusted", but determined by the load. Only by adjusting the "current adjustment" knob, the output current will change, and the output voltage will also change.
