
Tncks of the trade 299
transformer output circuit, the range over which
an active floating output such as in Figure 11.20b
can accept 'longitudinal' voltage variations
(common mode voltage variations with respect to
ground), coming back at it from the load circuit to
which it is connected, is limited by the rail supply
voltage from which the opamps run, and it also
eats into the available output voltage swing. When
the circuit is operated from batteries, this can be
alleviated by allowing the whole audio generator
plus batteries to float relative to its case. Stray
capacitance of the circuit and batteries to the case
will limit the amount o ...