Building an astable multivibrator circuit with a 555 timer

I haven’t built any sequential logic circuits since electronics school.  Back then,  a 555 timer was used as a clock source to drive JK flip-flops connected to the address lines of EEPROMS that contained programs I had written in hexadecimal.  In a world of super cheap Arduinos, raspberry pi’s, etc.  the days of making projects in that manner are long gone, for me anyway.   That was really fun stuff though, and I have a bunch of 555 timers in my parts bin.  So, I decided to tinker, and see if maybe I got some inspiration.

I built the astable multi-vibrator circuit straight out of the datasheet.

555 astable multi-vibrator
555 astable multi-vibrator
  • r1:  100K ohm
  • r2: 1M ohm
  • c1: 160nF

According the this awesome calculator, I’m running at about 4.3Hz with about a 50% duty cycle, which looks about right.

555 timer calculator output
555 timer calculator output
5 astable multivibrator circuit
555 astable multivibrator circuit

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