Combining 74HC74 & 555 Integrated Circuits

After working with some basic 74HC74 and 555 circuits, it was time to get fancy. I replaced one of the button triggers from my 74HC74 circuit with a 555 timer delay.

74HC74-555-button-wiring.png

Then I replaced the other button with a 555 timer delay as well.

555-74HC74-555-wiring.png

What do you think happens if I swap out the 22 μF capacitors for 4.7 μF? Remember the capacitor charge time formula from the 555 post? Multiply the capacitance (farads) by the resistance (ohms) to get the time. I’m still using the same 100 K ohm resistors.

t = RC

100000 * 0.0000047 = 0.47

So the delay decreases from 2.2 seconds to 0.47.

There is really no point in the 74HC74 here. You can connect two 555s to each other for a similar result. The video shows a double 555 circuit with 3 different timings, where I swap the capacitors from 22 μF to 4.7 μF and then 1 μF (delay of 0.1 second).

double-555-wiring.png

Are there any other circuits I should try with the 74HC74 and/or 555?

2 thoughts on “Combining 74HC74 & 555 Integrated Circuits

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