[sdiy] Non-inverting output buffer

[David G. Dixon]

One thing about putting the short-circuit protection resistor between the
opamp output and the feedback junction of a follower is that it doesn't
afford as much short-circuit protection as the same resistor beyond the
junction.

For example, a 1k resistor inside the junction will only limit the
short-circuit current to about +/-13.5V/1k = +/-13.5mA regardless of the
input , while that same resistor outside the junction will limit the current
to V_in/1k.

Indeed, 75R does not really provide any short-circuit protection, since the
output current would be +/-13.5V/75R = +/-180mA, which is well beyond the
current which most opamps can generate.