The circuit
is a preamplifier with digital regulation intensity of sound. He is separated
in three departments. In first schematic (Fig.1), is found the circuit
of control of electronic potesometer. The control become from two pressing
switches. The S1 (UP), that put up the intensity of sound and the S2 (DOWN),
on the contrary, that lower the intensity, checking them two oscillator
follow a bistable multivibrator R-S (ICIC-D), with that determined the
direction of counter IC3.. The gate IC2B ensure deactivate the counter
in the limits of region of regulation. With the S4 we have the possibility
selecting the level of sound, in which it will come back after RESET or
when we give supply in the circuit. This operation is very useful when
we select null level of sound, then with switch S3 we have the possibility
of going to situation MUTE, to rapid nihilism of sound. It will be supposed
you are careful the supply of circuit, which is symmetrical ± 8V. The logic
conditions, from outputs A,B,C,D drived on correspondingly
inputs IC2-3 in Fig.2, the points E,F,G linked on correspondingly outputs
from power supply (Fig.3). |
