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
- R1....4= 10Kohms
- R5....11= 820 ohms
- R12....21= 15Kohms
- C1= 100nF 63V MKT
- C2= 47uF 25V
- D1.....20= 1N4148
- IC1= 4511
- IC2= 4028
- Q1-10= BD679
- DSP1= Display 7 segment Common Cathode
- S1= 1X10 Step Selector
- RL1....10= 6V or 12V Relay
Source: http://www.hqew.net/circuit-diagram/How-to-build-Electronic-Selector-for-10-sources-with-Display$2dRelay-Drive_5985.html
