I'm using the 7805 as a variable regulator in a power supply, as I dont need voltage below 5v. The input power of the supply is +12v -12v DC (24v total). I have other regulators as well if they'd be better suited... lm317, 7912, a coupole LDO 5v and 12v, and lastly a variable 5-40v reg.
MY QUESTION IS... What would be the best way to drop the 7805's supplied input voltage from 24v down to ~15v? Diodes, power resistor, potential divider, DC-DC buck, cascade another higher rated v regulator?? I have a large heatsink and fan connected to the 7805 so maybe i'll be fine not needing to drop the input voltage? I just have no use for the higher volts and would like as much adjustment as possible with 15 turn pot being used. I had the 7805 connected across +5v -12v lines and didn't have any overheating issues, but the 5v line is now being used for a separate circuit. My goal is to have the voltage supplied to the load to be smooth and consistent without fluctuation due to heat.
Any input would be appreciated, thanks
also the current drawn is about 500-800ma, if that info is needed for anybody
MY QUESTION IS... What would be the best way to drop the 7805's supplied input voltage from 24v down to ~15v? Diodes, power resistor, potential divider, DC-DC buck, cascade another higher rated v regulator?? I have a large heatsink and fan connected to the 7805 so maybe i'll be fine not needing to drop the input voltage? I just have no use for the higher volts and would like as much adjustment as possible with 15 turn pot being used. I had the 7805 connected across +5v -12v lines and didn't have any overheating issues, but the 5v line is now being used for a separate circuit. My goal is to have the voltage supplied to the load to be smooth and consistent without fluctuation due to heat.
Any input would be appreciated, thanks
also the current drawn is about 500-800ma, if that info is needed for anybody