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uln2003/2803 problem

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Z.K.

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Either I have a bunch of bad 2003 and 2803 chips or I am doing something wrong in trying to get them to work. I tied pin 8 of the 2003 (pin 9 of 2803) to gnd, pin 9 (pin 10 of 2803) to +5v and I grounded pin 1 which is the first input. I should get a high out on pin 14 (16 on the 2803), but I don't. I get almost the same as the input about .05vdc. Am I doing something wrong? I am using the ground and +5v from an arduino. It should work as it can turn a relay on and off, but I cannot get the 2003 to work. I guess I just have some bad chips, but I thought I would check and see if there is anything else I need to do get this to work.

:confused:
 
The ULU2003 only pulls down. It can not pull up! If you look at the data sheet they show the load from supply (+5V) to the output pin. You need a load pulling up.
If there is nothing connected to the output pin it should never go high.
 
The ULU2003 only pulls down. It can not pull up! If you look at the data sheet they show the load from supply (+5V) to the output pin. You need a load pulling up.
If there is nothing connected to the output pin it should never go high.

Thanks, that makes more sense now.
 
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