The next step in Experiment 18 of Make:Electronics is the addition of a 555 timer in astable mode to the circuit (pg. 175 of the book). This addition drives the decade counter therefore the tactile switch that was connected to pin 1 of the first decade counter from the previous part of the experiment had to be removed. At first I had the two capacitor exchanged so instead of four pulses per second the display counted frantically. After solving this I encountered no further problem. For the larger capacitor connected to pin 6 of the 555 chip I used 100uF instead of the 68uF so my circuit is probably down to three pulses per second.
 |
| Circuit with the 555 timer included however the two capacitors (above the 555 timer) were exchanged. |
 |
| Circuit with the capacitors in the right place. |
Thanks for reading!