Digital Logic Fundamentals Unit 4 – Open Collector and Other TTL Gates
Exercise 2 – Transfer Characteristics of Gates
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to demonstrate the effects of an input
signal voltage level on the output logic state of a Schmitt-trigger LS inverter and a standard LS
inverter by using the OPEN COLLECTOR circuit block. You will verify your results by
comparing the output waveforms of each type of inverter.
EXERCISE DISCUSSION
- The STANDARD inverter changes state over a narrow voltage range that is between the
specified VIL and VIH. - The output of a Schmitt-trigger inverter changes state only at its specified VT+ and VT-; input
signals between VT+ and VT- are locked out. - A Schmitt-trigger gate transforms analog input waveforms into square digital output
waveforms.