Kryten New Member Mar 11, 2009 #1 Hi Would it be possible to connect a +5V and +15V to make +5V and -15V like this? Whit both regulators 78XX Attachments spenning.GIF 1.6 KB · Views: 144
Hi Would it be possible to connect a +5V and +15V to make +5V and -15V like this? Whit both regulators 78XX
C colin55 Well-Known Member Mar 12, 2009 #2 You cannot get minus voltage out of a regulator that has a positive voltage on the input. Let us know what type of transformer you have and we can perform some tricks.
You cannot get minus voltage out of a regulator that has a positive voltage on the input. Let us know what type of transformer you have and we can perform some tricks.
Sceadwian Banned Mar 12, 2009 #3 Apparently colin has never heard of switching regulators before =) There are plenty of regulators that can provide a -15 volt supply from a positive input. Both regulators being 78XX though? No, you can't do that, they're linear regulators.
Apparently colin has never heard of switching regulators before =) There are plenty of regulators that can provide a -15 volt supply from a positive input. Both regulators being 78XX though? No, you can't do that, they're linear regulators.
C colin55 Well-Known Member Mar 12, 2009 #4 Of course I know about switching supplies. But he did not talk about this type of arrangement. Last edited: Mar 12, 2009
ericgibbs Well-Known Member Most Helpful Member Mar 12, 2009 #5 Kryten said: Hi Would it be possible to connect a +5V and +15V to make +5V and -15V like this? Whit both regulators 78XX Click to expand... hi, Are the +5V and +15V currently two separate power supplies.???
Kryten said: Hi Would it be possible to connect a +5V and +15V to make +5V and -15V like this? Whit both regulators 78XX Click to expand... hi, Are the +5V and +15V currently two separate power supplies.???
Kryten New Member Mar 12, 2009 #6 No its from the same PSU a 12V mouse kind. and im actually using LM317. I guess i can use chargepump to make the -15V (ICL7662 is a nice one). The ponit is that only have 12V to start with so after thinking i know that i cant use the two regs.
No its from the same PSU a 12V mouse kind. and im actually using LM317. I guess i can use chargepump to make the -15V (ICL7662 is a nice one). The ponit is that only have 12V to start with so after thinking i know that i cant use the two regs.
Kryten New Member Mar 12, 2009 #8 not without opening the unit and that is a lot of hassle at this time. Other option is to use two of the powers to get +/-12V . would it then be possibel to get +5/-15V ? Its to drive the EL on a GLCD ( I think it might be damaged anyways but i want to try it)
not without opening the unit and that is a lot of hassle at this time. Other option is to use two of the powers to get +/-12V . would it then be possibel to get +5/-15V ? Its to drive the EL on a GLCD ( I think it might be damaged anyways but i want to try it)
ericgibbs Well-Known Member Most Helpful Member Mar 12, 2009 #9 Kryten said: not without opening the unit and that is a lot of hassle at this time. Other option is to use two of the powers to get +/-12V . would it then be possibel to get +5/-15V ? Its to drive the EL on a GLCD ( I think it might be damaged anyways but i want to try it) Click to expand... Do you have two power supplies on the bench.? if yes, what are their output voltages.??
Kryten said: not without opening the unit and that is a lot of hassle at this time. Other option is to use two of the powers to get +/-12V . would it then be possibel to get +5/-15V ? Its to drive the EL on a GLCD ( I think it might be damaged anyways but i want to try it) Click to expand... Do you have two power supplies on the bench.? if yes, what are their output voltages.??