electrode 14 the carry bit charge injection means includes a tompsett input comprising an input diffusion 32 formed in the substrate 1 an input gate 34 formed as a second level electrode connected to a constant voltage source v dc and a first level storage electrode 36 forming a surface potential well in the substrate 1 for storing the carry bit charge packet a second level electrode 38 is connected to a voltage source v r v sub u03b4 so as to form a potential barrier in the substrate 1 between the chsrge storage well located beneath the storage electrode 36 and the storage means in the substrate 1 formed beneath the electrode 14 the potential v r v sub u03b4 is selected so that a suitable surface potential barrier is formed in the substrate 1 beneath the electrode 38 in a manner well known to those skilled in the art the storage gate 36 is connected to substrate ground through a field effect transistor 40 having its gate connected to a gate voltage source v g charge stored in the first charge storing means beneath the electrode 14 is periodically removed by means of a reset electrode 42 connected to receive a clock signal u03c6rst and an output diffusion 44 connected to a voltage source v o the voltage v o is selected so that the output diffusion 44 forms an attractive repository for the removed charge transferred beneath the electrode 42 charge is periodically emptied from the floating diffusion 18 through a field effect transistor 46 connected to a drain voltage supply v dd the transistor 46 having its gate connected to receive a clock signal u03c6rst transfer of the carry bit charge.