The Op-amp Golden RulesFrom Horowitz & Hill:For an op-amp with external feedback
The Op-amp Golden RulesFrom Horowitz & Hill:For an op-amp with external "negative" feedback
But in real life the output will smack against one rail or the other and stay there.
Did you simulate it? (my link above, CircuitLab)Yes, Vout=Vin. Value of resistor doesn't matter. You can even put 0R.
there is a current gain even if there is no voltage gain.
Don't confuse more output current drive capability with current gain.
http://Cair to explain the difference then?
The BUF634 is a high speed unity-gain open-loopbuffer recommended for a wide range of applications.It can be used inside the feedback loop of op amps toincrease output current, eliminate thermal feedbackand improve capacitive load drive.For low power applications, the BUF634 operateson 1.5mA quiescent current with 250mA output,2000V/µs slew rate and 30MHz bandwidth. Bandwidth can be adjusted from 30MHz to 180MHz byconnecting a resistor between V- and the BW Pin.
You don't compute Iout/In in an opamp.
You don't call this beefier opamp as having "current gain"
If you look at a simple/typical opamp datasheet, you won't find this spec listed.
They don't call these opamps "current amplifiers" (or having current gain) just because it has a higher output current drive capability.