Forums » CircuitLab Feature Requests

Hi

I'd like to see a schmitt trigger NAND gate to be incuded. (aka the CD4093 )

Until such delights appear as building blocks in CircuitLab, you might like to have a look at:

which is based on:

As of right now, all digital inputs in CircuitLab have hysteresis (see the docs). The input is considered "low" when the input voltage drops below +2.0 volts, and becomes "high" when the input voltage rises about +3.0 volts.

Run this time-domain simulation:

We haven't yet exposed a way to configure those specific values, but @signality's approach works if you need that flexibility.

@mrobbins,

I'd missed that about the existing logic gates.

I maybe should put this in as a Feature Request but it fits in this thread anyway:

Do you have any plans to make parameters like output swing, rise and fall times or slew rates and output source and sink resistances available in the future?

You can make your own Schmitt trigger with a little positive feedback:

Simulates Nicely.

Cool, the fact that all digital inputs have hysteresis should be enough for now. I don' need that much flexibility. I know you can roll your own with an opamp, but the added complexity (and simulation time) lead me to my question here.