Wrong attribution, I didn't say that.

Lloyd E. Sponenburgh wrote:
Jim Stewart fired this volley in news:h0u6qq$jc8
:

A DC servo is just a DC motor with a feedback device.

Cybernetics theory (servo theory) says any "effector" with a feedback
element that the "driver" can read to control the effect is a "servo
system". It doesn't have to be a motor; could be a heater. Your air
conditioner is a cybernetic system.

That's one reason they call what we're discussing "servo motors", and
not (at least not correctly) just "servos".

LLoyd