How to build Electronic Selector for 10 sources with Display-Relay Drive

Description

This is a circuit for alternative sources selection. It combines mechanical selection using a rotating switch S1, the electronic drive of the relays RL 1-10 and also the optical indication of the selection by the Display DSP1. The function is based on the connection of the mechanical selections into 4 Bit (BCD) code. It is managed by the proper polarization of the diodes D1-10 and simultaneous convention into decimal output by IC2 which is a BCD to decimal decoder. The monitor is driven by the IC1, which is a BCD to 7- segment Latch/ decoder/ driver. We can made a lot of combinations and selections on the circuit. For instance, we may add Led' s in parallel with the RL1-10.

Circuit diagram

Part list

circuit from http://users.otenet.gr/~athsam/electronic_sel_10_step_d.htm