9v battery used in at89c51 | Microcontroller › 8051 › 9v battery used in at89c51 › 9v battery used in at89c51 August 31, 2015 at 12:11 pm #13236 Prabakaran P MParticipant Hi HIFZUL, It is not good to connect 9v battery directly to at89c51 it may harm it, You have to use 7905 voltage regulator to reduce the voltage to 5 volt.
