need help with a 555

Hi.
Im kind of new with the 555, so this question might be a bit stupid.
Well, I have to make a chronometer for my course of digital electronics with some counters (7490) and the clock signal is generated by a 555 and I need to make a button to pause the chronometer. Could anyone please help me with this? Thanks.

NE555 stop circuit

I think the easiest way is to put a 4.7k resistor from pin#4(reset) to the + supply rail. Connect a single pole normally open push button switch from pin#4(reset) to ground. When you push the the switch the 555 will stop and when you release the switch the 555 start again.

Hmm don't think you even have to mess with the time base (555) the 7490 as I remember ( old tech ) has a few set/ reset lines so you can use it as a stopwatch/chronograph. Get the pinout or spec sheet.

I need to make a button to pause the chronometer.

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That pause action doesn't have to latch does it? If so, you could use a D-latch or D flip-flop, if those are allowed.