I know that it is a very basic question but I really can not find an answer to it.
I would like to set my op amp to inverting amplifier mode so, I made the following circuit using LM358.
I vary the voltage of the inverting input of the op-amp using a variable resistance and a voltage divider.
I put 1 volt as an input, I expected to have -1 volt as an output but that doesn't happen. The output voltage is always zero ( ground ) or a very small value. I changed the input voltage from 2 to 12 volt, but the output voltage remains zero.
I used another power supply (5 volts) put I've got the same results which is zero volt at the output.
I saw some circuits on the internet and I found that the op amp is supplied with +9 volts and -9 volts, and the non inverting input is connected to ground. Does that mean I have to use a 3-terminal power supply ? Is there any other solution ?
I would like to set my op amp to inverting amplifier mode so, I made the following circuit using LM358.
I vary the voltage of the inverting input of the op-amp using a variable resistance and a voltage divider.
I put 1 volt as an input, I expected to have -1 volt as an output but that doesn't happen. The output voltage is always zero ( ground ) or a very small value. I changed the input voltage from 2 to 12 volt, but the output voltage remains zero.
I used another power supply (5 volts) put I've got the same results which is zero volt at the output.
I saw some circuits on the internet and I found that the op amp is supplied with +9 volts and -9 volts, and the non inverting input is connected to ground. Does that mean I have to use a 3-terminal power supply ? Is there any other solution ?