Relay logic shift register

Project Description

This circuit consists of a sequence of 4 relays activated one at a time by a clock signal, in other words a one-directional shift register. The logic is repetitive, so it can work for more relays.
Once the circuit is supplied no relay works, except the clock relays (K, K1).
By pressing the button for about one second the cycle starts and repeats.
Each relay is activated by an impulse of K (3-11) , but almost at the same time K1(1-9) opens. For that reason a 22uF capacitor is required. I used the diodes in order to prevent current back-flows, that would activate the relays in a missed sequence.
This shift register works fine with a pause of 1 second or more. If the time is shorter the clock relays may be stressed.

Video on YouTube

Figure 1