controlling a DC motor with ULN2003 problem

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raza_q

Joined: 13 Jan 2009
Posts: 2

13 Jan 2009 15:59 uln2003 circuit

hi all
Im trying to control a DC motor through my Laptop's parallel port using
ULN2003 IC but output on pin 15 is always high no matter input from LPT port is
0 or 1. Can someone help me out.

check out the circuit.
As far my knowledge goes ULN2003 should not conduct in the absence of an input on any of the input pins. Correct me if im wrong.

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daviddlc

Joined: 11 Feb 2007
Posts: 196
Helped: 13

13 Jan 2009 17:50 uln2003 dc motor

Based on the pin configuration the pin # 16 is not VCC.

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Sinisa

Joined: 03 Mar 2003
Posts: 337
Helped: 66

13 Jan 2009 18:09 uln2003 motor dc

Pin 9 should be connected to Vcc, pin 16 is output. Also, other motor lead should be also connected to Vcc, not GND. ULN has "open NPN collector output", which means it connects it's output to ground to close circuit. Read data sheets carefully before using IC's.