122-28176 Parallax Inc, 122-28176 Datasheet - Page 81

• Manufacturer Part Number: 122-28176
• Description: GUIDE STUDENT PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 122-28176

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Note the similarities in operation:
Another transistor configuration is the common-collector. What is common (emitter,
collector, or base) can be recognized by which terminal is NOT used by either the input
or the output. Consider the comparison in Figure 3-18 to a pushbutton switch.
The transistor will be in cutoff and act as an open-switch when insufficient V
to the transistor base. Just as with the pushbutton the output will be LOW through the
pull-down resistor.
When V
acting as a closed-switch and Vdd will be felt on the output (minus 0.3 V dropped across
the collector-emitter junction).
Figure 3-18 Switch Equivalent Common-Collector Configuration
N. O. Active High Switch with Pull-down
•
•
•
The pushbutton is activated by pressing it. The transistor is active (in saturation)
when sufficient voltage is applied to V
Both circuits have a HIGH output when the switch is not active through the use
of pull-up resistors.
Both outputs go LOW when the device is activated.
I
is a sufficient voltage, the base current will drive the transistor into saturation,
I
providing the base current required.
Common-Collector Configuration
I
is applied