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Electronics => Electronics => Topic started by: blackbeard on January 06, 2010, 02:22:16 PM

Title: negative voltage from 2 buffered sources?
Post by: blackbeard on January 06, 2010, 02:22:16 PM

i need to supply an op amp with +5v and -5v. if i have a single power source (i.e. a 9v battery) and 2 7805 voltage regulators would they be enough of a buffer to be used in the same circuit you would normally use with 2 9v batteries? (see the video below thoughtfully created by afroman).

Operational Amplifier Tutorial & super microphone circuit (http://www.youtube.com/watch?v=TQB1VlLBgJE#)

Title: Re: negative voltage from 2 buffered sources?
Post by: Soeren on January 06, 2010, 03:53:41 PM

Hi,

Quote from: blackbeard on January 06, 2010, 02:22:16 PM

i need to supply an op amp with +5v and -5v. if i have a single power source (i.e. a 9v battery) and 2 7805 voltage regulators would they be enough of a buffer to be used in the same circuit you would normally use with 2 9v batteries?

No, the 7805 needs 8V in and even if you discard that bit of info, 5+5 is usually 10 ;)

If you just wanna make a mic-amp., then you can just use the 9V and create an artificial ground (2 resistors and 2 caps should do in a nick).