A charge-coupled device or CCD (in Spanish "charge coupled device") is an integrated circuit containing a number of linked or coupled capacitors. Under the control of an internal circuit, each capacitor can transfer its electric charge to one or more of the capacitors that are at his side on the PCB. The digital alternative to CCD devices are the CMOS (complementary metal oxide semicondriver) used in some digital cameras and many webcams. Currently the CCD are much more popular in professional applications and digital cameras. In the diagram we can observe 1) photo-diode. 2) electron transfer register. 3) electric charge. 4) Horizontal Registry. 5) Output signal. 6) Amplifier. 7) Entry Light.