- #1
kostoglotov
- 234
- 6
I've checked documentation and it says anywhere between 3 and 30V to supply the LM324. But I couldn't find further guidelines.
My text explained that op amps need external power supplies, but provided no guidelines as to what value to make that supply value.
When analyzing this following circuit in PSpice, changing the power supply to the LM324's (even between 3 and 30) drastically changes the output voltages.
imgur link:
The top op amp has no feedback loop, so I figure its power supply should be higher than 5V to get to a saturation response.
This is my circuit in PSpice as drawn up in PSpice with some values shown next to Voltage sources.
imgur link: http://i.imgur.com/1h76t3y.png
According to the text, v0 should be -4.992V.
Now, if I take those op amp power supplies both to 30V, v0 becomes -5.005V...much closer to the text answer. Increasing op amp power supply beyond 30V causes no further changes, it seems to max out at -5.005V.
How are you supposed to know what power supply to use on an op amp? How does it depend on the circuit you're analyzing? What are some general guidelines?
Thank you in advance for any advice anyone can give :)
My text explained that op amps need external power supplies, but provided no guidelines as to what value to make that supply value.
When analyzing this following circuit in PSpice, changing the power supply to the LM324's (even between 3 and 30) drastically changes the output voltages.
imgur link:
The top op amp has no feedback loop, so I figure its power supply should be higher than 5V to get to a saturation response.
This is my circuit in PSpice as drawn up in PSpice with some values shown next to Voltage sources.
imgur link: http://i.imgur.com/1h76t3y.png
According to the text, v0 should be -4.992V.
Now, if I take those op amp power supplies both to 30V, v0 becomes -5.005V...much closer to the text answer. Increasing op amp power supply beyond 30V causes no further changes, it seems to max out at -5.005V.
How are you supposed to know what power supply to use on an op amp? How does it depend on the circuit you're analyzing? What are some general guidelines?
Thank you in advance for any advice anyone can give :)