Hello all!
I was playing around with 555 timer and 74 series logical ICs.
The first 555 is in astable mode, middle one is in monostable and lower one is bistable mode. The digital logic circuit selects either astable mode or monostable mode and puts the final output on pin 11 (labelled as clock) with SW1, a double throw switch as select switch (yes, it is 2x1 MUX). That bistable mode 555 debounces SW1.
Now the problem is that this "selection" is not good enough. When SW1 is at 3, astable mode is selected and I see a blinking led. BUT when I throw SW1 at 2, monostable mode should be selected but the behavior of led many a times is wrong. Led keeps flashing even if monostable mode is selected.
Whats more odd is this: You select astable mode for some time ( around 10 seconds or so) , SW1 is suddenly thrown to the other position to select monostable mode and when you press and HOLD SW4 to apply trigger, it takes some time for the led to go fully bright. HOWEVER, led works normally on further "short duration" SW4 presses (to me it sounds as if led is connected across a capacitor instead of a battery and capacitor is discharged when SW4 is free).
I have connected decoupling electrolytic capacitors of 1uf as instructed by this post: https://forum.allaboutcircuits.com/threads/decoupling-or-bypass-capacitors-why.45583/
BTW this whole thing is on solderless breadboard.
Thank you so much for you help.
I was playing around with 555 timer and 74 series logical ICs.
The first 555 is in astable mode, middle one is in monostable and lower one is bistable mode. The digital logic circuit selects either astable mode or monostable mode and puts the final output on pin 11 (labelled as clock) with SW1, a double throw switch as select switch (yes, it is 2x1 MUX). That bistable mode 555 debounces SW1.
Now the problem is that this "selection" is not good enough. When SW1 is at 3, astable mode is selected and I see a blinking led. BUT when I throw SW1 at 2, monostable mode should be selected but the behavior of led many a times is wrong. Led keeps flashing even if monostable mode is selected.
Whats more odd is this: You select astable mode for some time ( around 10 seconds or so) , SW1 is suddenly thrown to the other position to select monostable mode and when you press and HOLD SW4 to apply trigger, it takes some time for the led to go fully bright. HOWEVER, led works normally on further "short duration" SW4 presses (to me it sounds as if led is connected across a capacitor instead of a battery and capacitor is discharged when SW4 is free).
I have connected decoupling electrolytic capacitors of 1uf as instructed by this post: https://forum.allaboutcircuits.com/threads/decoupling-or-bypass-capacitors-why.45583/
BTW this whole thing is on solderless breadboard.
Thank you so much for you help.