Electronic Selector for 8 Sources

Description 

 The Elect. Sel. 8 is a simple circuit, with a choice of 8 sources of any sort ,of 8 independent switches. Each switch corresponding with a relay for example the switch S1 activates the RL1 e.t.c. The uses of the circuit are quite a few, choice of entrances in a sound amplifier, choice of command, in a digital circuit etc. In each entrance a LED which may be independent, except if switches with led are used. 

Circuit diagram

Part list

• R1-8=10Kohms
• R9=470 ohms
• R10-17= 4.7Kohms
• TR1=4.7Kohms Trimmer
• IC1=74LS374
• IC2=74LS27
• IC3=74LS10
• T1-8=BC550
• D1-8=Led 3mm
• C1-3=47nF 63V MKT
• RL1-8= 6-12V DC Relay
• S1-8=Push button SW 

Source http://users.otenet.gr/~athsam/Electronic_sel_8.htm