What is smith trigger?

[eugenehhk]

smith trigger

I am a beginner in electronic, I would like to ask what is smith trigger? What is the application?
Thx a lot~

 

[IanP]

smith trigger circuit

You have meant SCHMITT TRIGGER, not SMITH TRIGGER, haven't yuo?

Here is a good starting point:
https://en.wikipedia.org/wiki/Schmitt_trigger

Regards,
IanP

 

[haidi.elbahr]

trigger smith

I think it is called schemitt trigger

 

[the_risk_master]

smitch trigger

Its SCHMITT TRIGGER not (Smith Trigger - Wrong), it ia basically a comparator with a feature of hysteresis. Applications usually in digital electronics and power converters

 

[eugenehhk]

smit trigger

Thx All~
Is it means that the IC---LM311(Voltage comparator) is a kind of Schmitt trigger? Also I would like to ask what is the meaning of hysteresis? I know this term in Physics but why the Schmitt trigger has hysteresis?

 

[the_risk_master]

trigger de smith

Hysteresis is the difference between the input signal levels at which a comparator turns off and turns on. A small amount of hysteresis can be useful in a comparator circuit because it reduces the circuit's sensitivity to noise, and helps reduce multiple transitions at the output when changing state.

Sometimes, in a discrete design, there is a need to add an external resistor between the comparator's output and the positive input, creating a weak positive feedback loop. When the output makes a transition, the positive feedback slightly changes the positive input so as to reinforce the output change.

The LM311 Comparator IC is NOT a Schmitt Trigger device, but you can use it in a schmitt trigger circuit