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Doctors Medicines MCQs Q&A

  1. Negative edge triggering
  2. Positive edge triggering
  3. Positive level triggering
  4. Negative level triggering
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1 Answers

Option 2 : Positive edge triggering

Types of triggering

  • Level Triggering
  • Edge Triggering


Level Triggering:

  • There are two levels, namely logic high and logic low in the clock signal
  • Level triggering is of two types
    • Positive level triggering
    • Negative level triggering

 

  • If the sequential circuit is operated with the clock signal when it is in logic high, then that type of triggering is known as a positive level triggering.

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  • If the sequential circuit is operated with the clock signal when it is in logic low, then that type of triggering is known as Negative level triggering.

[ alt="F1 J.P 26.8.20 Pallavi D5" src="//storage.googleapis.com/tb-img/production/20/09/F1_J.P_26.8.20_Pallavi_D5.png" style="width: 394px; height: 87px;">

Edge Triggering:

  • Two types of transition occur in the clock signal. That means, the clock signal transitions either from logic low to logic high or logic high to logic low.
  • Types of edge triggering based on the transition of the clock signal.
    • Positive edge triggering
    • Negative edge triggering
  • If the sequential circuit is operated with the clock signal that is transitioning from logic low to logic high, then that type of triggering is known as positive edge triggering. It is also called as rising edge triggering.

 

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  • If the sequential circuit is operated with the clock signal that is transitioning from logic high to logic low, then that type of triggering is known as Negative edge triggering. It is also called as following edge triggering.

[ alt="F1 J.P 26.8.20 Pallavi D7" src="//storage.googleapis.com/tb-img/production/20/09/F1_J.P_26.8.20_Pallavi_D7.png" style="width: 391px; height: 81px;">

Positive Edge Triggered J.K. flip flop

  • In positive edge-triggered flip flops, the clock samples the input line at the positive edge (rising edge or leading edge) of the clock pulse.

[ alt="F1 J.P 26.8.20 Pallavi D8" src="//storage.googleapis.com/tb-img/production/20/09/F1_J.P_26.8.20_Pallavi_D8.png" style="width: 250px; height: 180px;">

  • The across the head at the clock terminal indicates positive edge triggering
  • The across head symbol is termed as a dynamic signal indicator 

 

[ alt="F1 J.P 26.8.20 Pallavi D10" src="//storage.googleapis.com/tb-img/production/20/09/F1_J.P_26.8.20_Pallavi_D10.png" style="width: 148px; height: 76px;">

Negative edge-triggered JK flip flop:

  • In negative edge triggered flip flops the clock samples the input line at the negative edge (falling edge or trailing edge) of the clock pulse.

[ alt="F1 J.P 26.8.20 Pallavi D9" src="//storage.googleapis.com/tb-img/production/20/09/F1_J.P_26.8.20_Pallavi_D9.png" style="width: 241px; height: 173px;">

  • A small circle is put before the crown head to indicate negative edge triggering.

[ alt="F1 J.P 26.8.20 Pallavi D11" src="//storage.googleapis.com/tb-img/production/20/09/F1_J.P_26.8.20_Pallavi_D11.png" style="width: 154px; height: 82px;">

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