In the attached project, I implemented a positive and a negative edge detector circuit. I am having a problem monitoring the output of both circuits. I can't seem to observe an edge in any of the expected ways:
When using probes or LEDs, I don't see edges. If I crank up the speed, I can see changes, but it doesn't seem to correspond to the expected pattern.
If I use the oscilloscope, I can clearly see the clock cycles, but the outputs don't change at all.
Figuring the problem may be due to frequency, I tried to use manual pulsing, but had no luck. Is there a way to monitor edges?
Thank you for your time and consideration.
P.S. I love LogicCircuit! I've tried several free and commercial packages and this was the easiest and most comprehensive product available for simple circuitry.
Hi,
You are on the right track but the program has circuits delay almost negligible. So in your circuit edges are sometimes detected and sometimes not. To make it more reliable you can use longer chains of inverters. I am sure 3 will be enough.
In order to observe your circuit working I’ve changed your source of clock signal to toggle button. Please power it up and click once to the button. Then you can double click on probes and see history of its values. The one connected to output of AND gate will have 0 1 0 which means it turned on and off as expected.
Oscilloscope will not help you as its showing state of the probes at the end of clock cycle.
Hope this helps.
Eugene
