|
In the top diagram, the
input voltage increases
from zero, along the
bottom horizontal line.
The output voltage
remains at zero on the
vertical line.
However, when the input
voltage reaches 1.7
volts, the output shoots
up from zero to 5 volts.
Reducing the input
voltage, as shown in the
top horizontal line does
not cause the output to
drop to zero
immediately.
This only happens when
the input voltage is
reduced to 0.9 volts.
The input level at which
the output increases to
maximum, and the level
at which it drops to
zero are different.
This is called
HYSTERESIS.
In the lower diagram
Schmitt Trigger action
is demonstrated in
another manner.
The black graph
represents a noisy logic
signal received from the
moon.
This is the input to the
Schmitt Trigger.
The green graph is the
output signal.
The output remains at
zero until the input
exceeds 1.7 volts.
The output then shoots
up to 5 volts and
remains at 5 volts until
the input drops to 0.9
volts.
The output then drops to
zero.
An almost perfect output
is recovered from a very
noisy input.
|
