With the popularity of AV audio-visual equipment , many families or units acquired players , camcorders , satellite receivers and other high-end audio-visual equipment . W for experienced enthusiasts , these AV devices to connect is not complicated ; but for layman terms , all kinds of AV signal line is easy to pick wrong . Once connected wrong , ranging from no map or silent , serious damage to AV equipment will be . This example describes the AV signal source selector , in addition to select the external AV signal source , but also on the power to control AV equipment , can effectively avoid a wrong AV signal line and misuse, but also reduce the variety of connection plug Line trouble is easy to use . Circuit works Reading of the AV signal source selector circuit from the power circuit , AV signal selection circuit and power control circuit , as shown in Figure 3-204 . Power circuit from the power transformer T, rectifier bridge pile UR, filter capacitor Cl5-C18 and the three-terminal voltage regulator integrated circuit IC2 composition . AV signal selection circuit switches from the high-frequency analog integrated circuits ICl, resistors Rl-Rl5, capacitors Cl-C14 and the signal outlet XSl-XSl2 composition . Power control circuit by the selector switch S ( composed by the Sa and Sb ), transistor Vl-V3, relay Kl-K3, diode VDl-VD3, LED VLl-VL3, resistors Rlg-R22 and the outlet XSl3-XSl7 composition . AC 220V voltage by T Buck , UR rectifier , Cl8 filtered into two-way : all the way through production + l2V voltage regulator IC2 , as ICl of the working power ; another buck passing Rlg limit , the supply of power control circuit . AV signal selection circuit switch 3 Group AV sync signal ( all the way video and two stereo audio signal) . ICl of Vl, V2 and V3 side were VCR ( photo , video signal ), LD (CD, VCD, DVD players and other signals ) and BS ( satellite receiver signal) of the video signal input ; ARl, AR2 and AR3 -side Respectively, VCR, LD and the BS of the right channel audio signal input ; ALl, A client was ashamed and AL3 VCR, LD and the BS of the left channel audio signal input ; V, AR and AL after the end of the video were selected Signal , there -channel audio signal and the left channel audio signal ; M side (15 feet ) for the signal source selection control side . When used with a signal line to the camera , VCR, DVD players and satellite receivers and other AV equipment, audio and video signal output respectively XSl-XS9 in the corresponding input socket connected to XSlO (VOUT) and the TV or the power Connected to the audio amplifier input . The S placed in the " 1 " position , ICl of the M -side is high , ICl select output source for the VCR, while Vl turn , Kl pull , VLl light , XSl3 (VCR) is the power outlet Connected . The S placed in the " 2 " position , ICl of the M -side suspension , select the output of the signal source for the LD, while V2 conduction , K2 pull , VL2 light (Vl end , Kl release , VLl out ), XSl4 outlet (LD) of the power supply is connected . The S placed in the " 3 " position , ICl M- grounded, and select the output of the signal source for the BS, while V3 turn , K3 pull , VL3 light (V2 end , Pakistan released , VL2 out ), XSl5 outlet (BS) power is connected . Components Selection Rl-R18 and R2O-R22 are selected 1/4W metal film resistors ; Rl9 use 1/2W metal film resistors . Cl-ClO, Cl2-Cl5 were selected voltage value 16V aluminum electrolytic capacitor ; Cll and C16, C17 multilayer ceramic capacitors are used ; C18 use of capacitors for voltage value of 25V . VDl-VD3 1N4007 type silicon rectifier diodes are used . VLl-VL3 were selected f3mm ordinary light emitting diodes UR selected 5OV, lA of the rectifier bridge pile . Vl-V3 are all made of 58050 or C8050, 3DG8050, 3DGl2 silicon NPN transistor . ICl use M51321P high frequency analog switch ASIC ; IC2 use LM78L12 or AN78L12 three-terminal regulator IC type . Kl-K3 are used 4098 -type 12V DC relays . T use 5W, the second voltage l5V power transformer . S -band switch selected bipolar 3 .