Hi i am weak in circuit design. Can anyone suggest to me what circuit can i build to detect a change periodic pulse. Basically i have a periodic pulse and i want to detect if its frequency changes. I am looking at LM358 comparator but having trouble. I have limited component to used. What is the simplest circuit/component i can build to achieve that

Thanks John

 

Connect the LM358 to detect the pulse and light an LED. Then watch the LED and record it's on and off times with a stop watch.

 

Google: "missing pulse detector" circuit
Google: "frequency to voltage converter" circuit

Ken