| Electronics > Projects, Designs, and Technical Stuff |
| 74HCT74 NXP vs Texas |
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| Jan Audio:
Ok, many thanks. Why did NXP quit ?, and why dont Texas has schmitt-trigger ? I will take a look for other vendors, its for personal use only, thanks for the advice. I also dont like to use more space on my circuit for a schmitt trigger. Maybe Texas themself has also with schmitt trigger, i,m gonna find out. |
| Zero999:
Use a potential divider: R1 = 4k7 R2 = 3k3 I used the site linked below to calculate the resistor values, which I divided by 10, to give more speed and noise immunity. https://www.random-science-tools.com/electronics/divider.htm |
| Jan Audio:
You cant divide 6,6volt off state and 11,5volt on state, the zener is needed also. |
| Zero999:
--- Quote from: Jan Audio on December 26, 2018, 06:41:08 pm ---You cant divide 6,6volt off state and 11,5volt on state, the zener is needed also. --- End quote --- You're right, I missed the 6.6V and 11.5V part. The resistor values could be changed, but it would be marginal. If you knew that, then why didn't you mention the zener diode before? Change R2 for a 4.7V or 5.1V zener diode and keep R1 the same. --- Quote from: Jan Audio on December 26, 2018, 01:55:08 pm ---I have no zeners in house, another parts series to buy ?, do i really need them... --- End quote --- Zener diodes are not expensive. |
| Jan Audio:
The zeners might be usefull, i go look for those. I think the chip wont break since the difference is about 5 volt. + the saw is also a slow ramp. As long it works im happy for now, going to solder a new circuit. |
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