8051 based relay control.

Discussion in 'Embedded Systems and Microcontrollers' started by tepu, Feb 11, 2015.

  1. tepu

    Thread Starter New Member

    Feb 11, 2015
    1
    0
    Dear All
    I want to controll relay of 5vdc from microcontroller 89c52.I want to know that i have to connect signal pin to relay circuit directly or it requre pull ups in betwen controller & relay circuit?
     
  2. absf

    Senior Member

    Dec 29, 2010
    1,492
    371
    If only one relay use a NPN transistor to drive relay. If more than one then use ULN2003 darlington drivers.

    If using Port 0, pullup resistor is required. P 1,2,3 got internal pullups.

    Allen
     
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