I have a bunch of unused CD4098 ICs available and I was hoping to use them in DIY-project to drive a counter (therefore duty cycle % does not matter) in astable multivibrator mode with adjustable frequency. Schematic for this is straightforward using both packaged multivibrators:

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However I was wondering if it's possible to use two multivibrators available in CD4098 to drive two independent counters and use only one of CD4098 in my design. Internal logic of CD4098 is as follows:

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Since multivibrators are monostable additional logic should probably be used. My first thought is to add NAND gate to NR pin:

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My though process for this schematic is as follows:

  1. starting with Q=0 leads to NR=1
  2. NR=1 leads to Q=1 after T=RC/2
  3. Q=1 leads to NR=0
  4. NR=0 leads to Q=0

[cycling continues via steps 1-4 with a period slightly larger then T=RC/2]

I would appreciate if somebody could comment on this idea or propose a better implementation of converting each monostable subunit of Cd4098 into astable multivibrator.



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