I started with an original circuit containing a 555 in astable mode driving a pair of 4015s and a 4017. These in turn were used to switch on 15 and 4 LEDs, respectively. This circuit ran fine between 9 and 12 volts, from both batteries and a power supply.
The values used on the 555 was:
C1=1uF electrolytic
R1=47k 1/4 Watt
R2=100k trimpot
The next iteration was to use a 556 so the 4015s and 4017 could be driven at independent rates. I did some 555 math to tweak the timing of the chips to allow a different "center" and the results for the 556 are as follows:
Driving the 4015s:
C1=1uF electrolytic
R1=22k 1/4 Watt
R2=50k trimpot
Driving the 4017:
C1=2.2uF electrolytic
R1=100k 1/4 Watt
R2=50k trimpot
This 556 is also being run in astable mode. The issue that I have is that while this circuit runs beautifully at 9V, when powered with 12V, it proceeds to light the LEDs in an erratic pattern. I've found some mention of higher voltages and edge trigger and such, but nothing I could figure out.
I'm not sure if the caps need to be a different value, or if the resistors are wonky or what. I've tried slightly different values for each, and it's not changing anything. It's just really strange to me that (V would work perfectly, and 12V messes up, and all that really changed was going from a 555 to 556.
Any help would be appreciated, since I'm getting frustrated.
The values used on the 555 was:
C1=1uF electrolytic
R1=47k 1/4 Watt
R2=100k trimpot
The next iteration was to use a 556 so the 4015s and 4017 could be driven at independent rates. I did some 555 math to tweak the timing of the chips to allow a different "center" and the results for the 556 are as follows:
Driving the 4015s:
C1=1uF electrolytic
R1=22k 1/4 Watt
R2=50k trimpot
Driving the 4017:
C1=2.2uF electrolytic
R1=100k 1/4 Watt
R2=50k trimpot
This 556 is also being run in astable mode. The issue that I have is that while this circuit runs beautifully at 9V, when powered with 12V, it proceeds to light the LEDs in an erratic pattern. I've found some mention of higher voltages and edge trigger and such, but nothing I could figure out.
I'm not sure if the caps need to be a different value, or if the resistors are wonky or what. I've tried slightly different values for each, and it's not changing anything. It's just really strange to me that (V would work perfectly, and 12V messes up, and all that really changed was going from a 555 to 556.
Any help would be appreciated, since I'm getting frustrated.