I have a circuit for interfacing relay with parallel port
the relay will control another circuit ( bulb )
I'm using ULN 2803 IC , so that whenever pin 1 of this IC got a 1 value from the parallel port .. the relay will be operated
but since I'm using the proteus for the first time .. I didn't know how to use the connector so I replaced it by ( logic state ) , when it's 1 the relay should work << I thought this would work fine !
this is my circuit when I simulate it , nothing happend for the relay
what should I do to make it run correctly ?
really !
yes I've check it now it's 12 v
I noticed that when I simulate , the voltage in pin 18 goes to 10 v and it should goes to zero
when I change the IC to another one .. pin 18 goes to 0 volt and the circuit run fine .. I don't know what's the problem with this ULN2803