Schmitt Trigger

First decide supply voltage and transistor gain.
Vcc= volt
Now compute either resistors or voltages:
Icc= amp
Vlow= 0.6 to 0.9 volt
Vhigh= volt
R2= ohm
R3= ohm
R4= ohm
R1= ohm
Resistor R1 limits input current and
reduces ripple of output low voltage.
The value of R1 is not critical.
Resistor R2 value is not very critical
but if it is chosen to be bigger than
the calculated value, output high state
voltage will drop.
© 2004 Tom Ahola