niukasu
Newbie level 1
I am a student without any EE background.
I noticed that there are some posts answering how to use ULN2003A, but it does not work for me.
Take this one as an example,https://www.ti.com/lit/ds/symlink/uln2003a.pdf
I connected 2 9V battery and a relay in series. Then I connected the positive side to 1C, and the negative side to COM. After that, the relay switched.
I don't understand why. Doesn't it require an input in 1B if I want 1C work?
What should I do to make the relay switched work only if there is an input in 1B? The current situation is the relay switches even though there is no input in 1B
I noticed that there are some posts answering how to use ULN2003A, but it does not work for me.
Take this one as an example,https://www.ti.com/lit/ds/symlink/uln2003a.pdf
I connected 2 9V battery and a relay in series. Then I connected the positive side to 1C, and the negative side to COM. After that, the relay switched.
I don't understand why. Doesn't it require an input in 1B if I want 1C work?
What should I do to make the relay switched work only if there is an input in 1B? The current situation is the relay switches even though there is no input in 1B