nsguiamano
Junior Member level 1
I'm trying to use an LM358 as a voltage comparator to test the voltage of a battery connected at the output of my system.
(I know that I can use an actual comparator IC like LM339, but I'm trying to do it using the 358 so please bare with me)
I'm only using one of the opamps and left the +/- input pins and output pin of the other opamp not connected.
Shown below are picture of the connections.
AC_15V is just 15Vdc from a power supply.
For the battery terminal, I just connected a DC supply which I change from 0-12V to adjust the input 12V+ to the opamp.
Nothing else on the board is connected since I'm testing this part only.
Problem is, when I change the voltage at the battery terminal, the output of the opamp is not change from 0 to 5 (or vice versa) as expected.
Any thoughts? I'd like to keep my IC as LM358 cause I've been able to use it as a comparator before and can't figure out why it's not behaving the way I expected this time.
Thanks.
(I know that I can use an actual comparator IC like LM339, but I'm trying to do it using the 358 so please bare with me)
I'm only using one of the opamps and left the +/- input pins and output pin of the other opamp not connected.
Shown below are picture of the connections.
AC_15V is just 15Vdc from a power supply.
For the battery terminal, I just connected a DC supply which I change from 0-12V to adjust the input 12V+ to the opamp.
Nothing else on the board is connected since I'm testing this part only.
Problem is, when I change the voltage at the battery terminal, the output of the opamp is not change from 0 to 5 (or vice versa) as expected.
Any thoughts? I'd like to keep my IC as LM358 cause I've been able to use it as a comparator before and can't figure out why it's not behaving the way I expected this time.
Thanks.