hi
i m using at89s52 in my project... i need to drive a relay using it. i m using a transistor to drive the relay and the output from the microcontroller goes to the base of transister via resistance... the relay works properly when base is connected to 5 volt supply and it consumes 4.2mA but when i connect the base to the pin of at89s52 (through a resistance) the output voltage of the pin drops significantly to 0.67 V from 5 V.... i don't know why this is happening.... i tried reprogramming the microcontroller but all in vain... due to voltage drop the relay is not functioning... please help asap......
hasta la vista
i m using at89s52 in my project... i need to drive a relay using it. i m using a transistor to drive the relay and the output from the microcontroller goes to the base of transister via resistance... the relay works properly when base is connected to 5 volt supply and it consumes 4.2mA but when i connect the base to the pin of at89s52 (through a resistance) the output voltage of the pin drops significantly to 0.67 V from 5 V.... i don't know why this is happening.... i tried reprogramming the microcontroller but all in vain... due to voltage drop the relay is not functioning... please help asap......
hasta la vista