Fade=in volume control for audio amplifier - has regulating stage with integrating stage to provide approximately linear characteristic

摘要

A fade out circuit for use with low frequency amplifiers is designed to sudden changes in signal during switch-on or switch-off. The circuit provides an approximately lnear characteristic. Between the signal source (1) and the amplifier (2) is located a volume control stage (3), consisting of a transistor (5) and a resistor (6). The regulating input is provided by a regulator (17), consisting of a d.c. amplifier (18) operating as an integrator. The input is provided over the on-off fade key (9) coupled to a source (23). A threshold value amplifier may be connected between the two stages in a more elaborate version of the circuit.