VOLUME CONTROL APPARATUS

摘要

A volume control apparatus wherein a master volume control resistor is controlled by a motor and a control circuit is provided for the motor which includes a presettable-variable resistor and a slave-variable resistor which is driven by the output shaft of the motor. A first comparator is connected to the presettable-variable resistor and to the slave-variable resistor which are in turn connected across suitable supply voltages and depending upon the relative voltages across these resistors a motor control discriminator circuit operates the motor in either the clockwise or counterclockwise direction to vary the master volume control and the slave-variable resistor until the slave-variable resistor is substantially equal to the presettable-variable resistor. When the resistance of the slave-variable resistor approaches the presettable-variable resistor the output of the master volume control is connected to an output speaker by a relay circuit.