A high frequency CIS capacitance device having a substrate of one conductivity type provides a capacitance for a high frequency signal applied across a pair of capacitance electrodes thereof which is dependent on the voltages applied to a pair of control electrodes, each connected to the surface adjacent region of the substrate underlying one of the pair of capacitance electrodes of the device through a respective channel region of opposite conductivity type. Means are provided for alternatively establishing one or the other channel regions of opposite conductivity type to establish values of capacitances dependent on the voltages applied to the control electrodes. Composite devices are formed of elemental devices such as described in which the capacitance of the composite device is the sum of the capacitance of the elemental devices and is variable in discrete increments to provide a large number of discrete values of capacitance in response to digital signals applied to a minimum number of control electrodes connected thereto.