A Schmitt Trigger is a type of electronic circuit that converts an analog input signal into a digital output signal. It is used to clean up noisy signals and provide a stable output.
A Schmitt Trigger has two input thresholds, a high threshold (Vth) and a low threshold (Vtl). When the input voltage (Vin) is above the high threshold, the output (Vout) switches to a high state. When the input voltage is below the low threshold, the output switches to a low state. The output remains in the same state until the input crosses the opposite threshold.
Vref is the reference voltage used to set the high and low thresholds of a Schmitt Trigger. It is typically set to be halfway between the high and low thresholds to provide symmetrical switching behavior.
The output voltage of a Schmitt Trigger can be calculated using the following formula: Vout = Vref + (Vin - Vref) * (1 - 2*(Vth - Vtl)/(Vin - Vtl - Vth)).
The values for Vref, Vth, and Vtl should be chosen based on the input signal and the desired output behavior. Vref should be set to be halfway between Vth and Vtl for symmetrical switching. Vth and Vtl should be chosen to provide a suitable hysteresis (difference between the two thresholds) to avoid false triggering.
