hai,

im using 89c52 for my project, i want to connect the relay to the port1.0 pin. so i gave P1^0 to resistor value of 1K and to BC547. when i give pulse1 to the pin i get 0.69V instead of 5V.

i used pullups then it worked. but i studied intthe datasheet that port1 need not any pullups. pls help in this topic.

thank u.