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How can i combine 555 oscillator with a J-K flip-flop to produce a perfect(50% duty cycle) square wave?
1st question.
Design a 555 free-running oscillator to produce an approximate square wave at 40 kHz. C should be kept at 500 pF or greater.
Answer:
(Ra = 1k, Rb = 10k, C = 1800 pF).
2nd question:
A 555 oscillator can be combined with a J-K flip-flop to produce a perfect (50% duty cycle) square wave. Modify the circuit of question 1 to include a J-K flip-flop. The final output is still to be a 40kHz square wave.
1 Answer
- 1 decade agoFavorite Answer
J-K's will toggle its output Q between 0 and 1 on every clock cycle when J=K=1
So, tie J and K to the 5V rail, and tie your 555 output to the clock input of the flip-flop. This will give you a 50% duty cycle square wave. However to keep it at 40kHz, you need to clock it at twice the frequency if I'm not mistaken.