We found this code switch circuit in the January 1999 Electronics Now magazine. Some of the components are integrated circuits from that era.
This simple circuit, powered by 4 batteries or 9 V battery, brings together several functions of...
Figure 1 shows how the 4029 can be connected to count up to 10 and also up to 18. If pin 9 is...
I found this circuit in an old English magazine from 1979, but it can be easily assembled with...