I'm using a DC power supply connected to a TPIC 1021 chip(basically a serial transceiver). I need 12V to power the chip and my DC power supply is equipped with 2 knobs,one changes the voltage and the other changes the current. For some reason,when I get to 5V and turn the volt knob further,the power supply switches automatically to current mode i.e the LED on current indicator turns on. I can't go further than 5V unless I turn the current knob a little and only after that do I can get to turn to 12V. Step a. I turn the voltage knob to 5V. The voltage LED switches off and the current LED turns ON. Step b. After my current LED turns ON,I turn the current knob just a little ->Now my voltage LED turns back ON and only now do I get to change the voltage to 12V. Why does this happen? 1.Is it because there's a possible short-circuit? 2.Has it got something to do with Power=Voltage*Current ? [Its weird that the power supply could supply 5V at 0 ampere and not 12V at 0 amps]. Your views please.