Schmitt Triggers...

[Ginsly]

The PWM is on my list to build, and it requires a CD40106 Schmitt Trigger. I plan on getting the necessary chip, but I oddly have a different ST chip, an NTE74ls14.

I'm not familiar with this kind of component, and was wondering - could one sub for the other in this schematic? I've looked at both datasheets but I'm not sure what to look for in this case.

CD40106B: https://www.ti.com/lit/ds/symlink/cd40106b.pdf?ts=1721608238726

NTE74ls14: https://www.nteinc.com/specs/7400to7499/pdf/nte74LS14.pdf

Here's the project:

 

[jwin615]

At a glance, may work if you only use pin1-7.
Throw it in the BB and find out.

 

[Coda]

Sounds like a load of Bull Schmitt…

 

[Ginsly]

At a glance, may work if you only use pin1-7.

Huh! But wouldn’t I be missing important parts of the equation in the other 7 pins? Sounds like they may not be all that compatible…

Sounds like a load of Bull Schmitt…

The elusive “Chip-Based Dad Joke”. IC ‘em, but not often.

 

[Paul.Ruby]

I doubt it will sound the same because the output section of TTL logic is very different than CMOS. CMOS has symmetrical pull-up and pull-down. TTL is very strong pull-down and much weaker pull-up. So, they may sound very different.

 

[Paul.Ruby]

Also, TTL is very strictly 5VDC while CMOS is more forgiving and could run at 9V.

 

[Ginsly]

I doubt it will sound the same because the output section of TTL logic is very different than CMOS. CMOS has symmetrical pull-up and pull-down. TTL is very strong pull-down and much weaker pull-up. So, they made sound very different.

Ahhh ok, there it is. I didn't realize the other one wasn't CMOS. Will order the 40106 as planned, thanks much!

 

[Paul.Ruby]

Just for completeness sake... TTL inputs are also very different. The input is much lower impedance on pull-down (must sink current on the emitters of bipolar transistors) than on pull-up, which is high impedance. CMOS is high impedance input (gates of FETs).

 

[jwin615]

Huh! But wouldn’t I be missing important parts of the equation in the other 7 pins? Sounds like they may not be all that compatible…

The elusive “Chip-Based Dad Joke”. IC ‘em, but not often.

Only need 2 triggers. But I didn't notice it was TTL.