as noted above,dc control lends itself to computer and remote control systems since they operate off specific fixed dc levels. for instance,when an infrared (IR) signal is sent out by a remote control to the receiver in a TV or VCR,the signal is passed through a decoder-counter sequence to define a particular dc voltage level on a staircase of voltage levels that can be fed into the gate on the JFET. for a volume control,that gate voltage may control the drain resistance of a non inverting amplifier controlling the volume of the system