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I have been studying op-amps in my 2nd year circuits class and I had a question to ask.
From what I understand the output voltage is supposed to be < power supply voltage.
If this is the case, why do we use op-amps ?
I mean if I have 15V and I need to power something why can't I just use the 15V instead of using an op-amp only to realize 13V as my output voltage ?
For example if I have an ideal inverting opamp powered by 15V, -15V dc my output voltage is approximately
[tex]V_{o}[/tex]= -([tex]R_{f}[/tex]/[tex]R_{1}[/tex])* [tex]V_{i}[/tex]
Where Rf is my feedback resistance, Vi is my input voltage connected to my non inverting terminal and R1 is my resistor connected to my inverting terminal.
Why can I just put Vi = 30 V ( supposing Rf > R1) and get |Vo| > 30V ? I know it would "saturate" theoretically but what is wrong with that ?
When we saturate the circuit does this mean that Voutput= Vpowersupply or does that it mean I can get more voltage but my op-amp would not be working in a "safe" mode ?
In summary I thought and op-amp would amplify voltage but it doesn't seem to be true. I mean it take a input voltage and then spits out a bigger value which is limited by the power supply. I thought all circuits would function properly as long as the power balance equation is satisfied ?
If I have 15V to waste by should I plug it into an op-amp instead of using it directly on my device ?
From what I understand the output voltage is supposed to be < power supply voltage.
If this is the case, why do we use op-amps ?
I mean if I have 15V and I need to power something why can't I just use the 15V instead of using an op-amp only to realize 13V as my output voltage ?
For example if I have an ideal inverting opamp powered by 15V, -15V dc my output voltage is approximately
[tex]V_{o}[/tex]= -([tex]R_{f}[/tex]/[tex]R_{1}[/tex])* [tex]V_{i}[/tex]
Where Rf is my feedback resistance, Vi is my input voltage connected to my non inverting terminal and R1 is my resistor connected to my inverting terminal.
Why can I just put Vi = 30 V ( supposing Rf > R1) and get |Vo| > 30V ? I know it would "saturate" theoretically but what is wrong with that ?
When we saturate the circuit does this mean that Voutput= Vpowersupply or does that it mean I can get more voltage but my op-amp would not be working in a "safe" mode ?
In summary I thought and op-amp would amplify voltage but it doesn't seem to be true. I mean it take a input voltage and then spits out a bigger value which is limited by the power supply. I thought all circuits would function properly as long as the power balance equation is satisfied ?
If I have 15V to waste by should I plug it into an op-amp instead of using it directly on my device ?