hi frds,

i have problem with port.

i have 89c51 mc and programing done is such that port P1.0 is high for 18 sec and low for other 18 sec.i need to amplify.

when i connected the port output to base of bc548 transistor to amplify and connected one lead of led to collector and another to vcc.and emitter is grounded.

and when there was power on led started glowing when signal at port was high and remained glowing even when port signal was low
(no base in put).i feel that thas the probl;em with base leakage current.

i dont know how to post my schematic i dont have scanner how to post.


please specify solution