How do you tell the difference between an inverting Op-Amp and a non-inverting Op-Amp?

Question

How do you tell the difference between an inverting Op-Amp and a non-inverting Op-Amp?

Answer 1

The input common mode range spec gives an indication of the maximum input voltage. In some op-amps this is considerably less than the supply, even 1/2. The maximum output voltage is also less than the supply. Also consider the maximum supply voltage, most op-amps can not have > +/- 20V. WOrk with lower signal voltages unless dynamic range is a real issue. If it is use low noise op-amps. The inverting summer is what you should be using. It has a number of advantages, but it uses a virtual ground at the input, so the input voltage is virtually zero. The output is related to the gain, and yes you need to sum the peak voltages for the combined peak. If you are concerned about input impedance use a low bias current op-amp with higher resistors like 1 meg-ohm, or an input buffer amplifier. If you are concerned about polarity, use op-amps at input or output to get the polarity you want. It is normal to leave some overhead too, in case the signals are bigger than expected. This applies particularly with speech and music where the factor of peak to average can be many times. Work with the peak voltages. The link below explains the inverting summing amplifier.

Answer 2

By the terminal in to which the signal input enters. If it enters the + labeled terminal, then the Op-Amp is a non-inverting Op-Amp. If it enters the - labeled terminal, then the Op-Amp is an inverting Op-Amp (which FYI, most stable Op-Amp configurations that are useful will be an inverting amplifier of some sort).





In any case, for the two "golden rules" of Op-Amps to apply, you MUST have a feedback line connected to the - input terminal. OTHERWISE, you don't have an amplifier, you have either a Schmitt trigger or an inverting comparator.

Answer 3

You should draw the circuit and you will find the difference. It is not that you can use an amplifier such as 741 only for inverting or non inverting configuration. It all depends on the circuit in which it is used.

In inverting amplifier as example, you can feed 1V at 100Hz to -ve input through a 100k with feedback (mind you.. negative feedback) from negative input to output through a 100k. The positive input is grounded.

Apply the supply and enjoy seeing an inverted output also of 1V. (If you like, you can compare the input with output in a CRO..or a simulator such as circuit maker..(free download).

In the non inverting configuration, the negative input is grounded through a 100k. With feedback as earlier, input is applied to positive input. You will get 2V output and it will be in phase with input.

Answer 4

All op amps are basically the same. The "circuit" becomes inverting or not depending on how you hook it up.

Answer 5

The sign of the output of an inverting amplifier is opposite to that of its input.



i.e. a positive, or positive-going, input results in a negative, or negative-going, output.







The sign of the output of a non-inverting amplifier is the same as the sign of its input.



i.e. a positive, or positive-going, input results in a positive, or positive-going, output.







There is no phase change, simply inversion or no inversion.



veeyesvee is confused.