| ??? 02/17/09 19:19 Read: times |
#162527 - re: transfer function Responding to: ???'s previous message |
Ap Charles said:
Yes I need that transfer function (Vout=V2) . I mentioned LMP2234 which has an absolute maximum spec says "+/-300mV maximum input differential voltage" (Do I really need to go with absolute maximum ratings?) .I conclude from this is that the opamp won't work. You need to go back to op-amp school. The maximum differential input voltage is the maximum voltage you can apply to the op-amp's input pins, + and -, and expect the device to function as an op-amp. Why? Because remember one of the Golden Rules of op-amps: the voltages at the input pins are always equal. Now the voltages at the op-amp input pins are rarely the [i]circuit's[/i] input voltages. The circuit includes the feedback and other resistors! So you can certainly have a difference amplifier that subtracts 12 V from 15 V. Look up difference amplifiers in the Horowitz and Hill book, "The Art Of Electronics." -a |
| Topic | Author | Date |
| Opamp question | 01/01/70 00:00 | |
| Please specify! | 01/01/70 00:00 | |
| Oops here its | 01/01/70 00:00 | |
| Mistake? | 01/01/70 00:00 | |
| transfer function | 01/01/70 00:00 | |
| Vout = V2 ? | 01/01/70 00:00 | |
| I 'm entirly confused... | 01/01/70 00:00 | |
| I explain it again | 01/01/70 00:00 | |
| So Vout = V2 - V1 | 01/01/70 00:00 | |
| I do have a common GND | 01/01/70 00:00 | |
| So Vout = V2 -15 ? | 01/01/70 00:00 | |
| trying to achieve | 01/01/70 00:00 | |
| Reference | 01/01/70 00:00 | |
| Reference | 01/01/70 00:00 | |
| Much clearer but.. | 01/01/70 00:00 | |
| Not clear | 01/01/70 00:00 | |
What VOut range do you want? | 01/01/70 00:00 | |
| I think this will do the trick... | 01/01/70 00:00 | |
| re: transfer function | 01/01/70 00:00 | |
| re: transfer function | 01/01/70 00:00 | |
| Ohm's law | 01/01/70 00:00 | |
| Oh the internal protection of opamp! | 01/01/70 00:00 | |
| Errr... | 01/01/70 00:00 | |
| Don't confuse "OPamp" with "OPamp circuit"! | 01/01/70 00:00 | |
| Don't confuse "OPamp" with "OPamp circuit"! | 01/01/70 00:00 | |
| If the feedback loop doesn't work... | 01/01/70 00:00 |