130-28176 Parallax Inc, 130-28176 Datasheet - Page 80

• Manufacturer Part Number: 130-28176
• Description: KIT PARTS PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 130-28176

• Accessory Type: Education Kit
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Board of Education Full Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Ideally, the output impedance of a device should be zero, and the input impedance should
be infinite to transfer the maximum voltage. Since we don't live in an ideal world, the
input impedance should be at least 10 times the value of the output impedance between
devices so that loading effects are not an issue. For example, if the input impedance of a
device is 1 MΩ, the output impedance of the device supplying it should be no more than
100 kΩ.
Using the transistor as an input from another device, a higher base resistance is desirable
to prevent loading and excessive current from the supplying device. Note that the control
of the transistor is dependent on base current. As long as R
voltage may be smaller or larger than Vdd. This allows a means to interface devices
operating at different supply voltages.
ACTIVITY #6: SWITCHING CONFIGURATION COMPARISONS
Figure 3-17 is a comparison of an Active-Low pushbutton switch and the common-
emitter transistor circuit that we have been using.
Figure 3-17 Switch Equivalent Common-Emitter Configuration
N. O. Active Low Switch with Pull-up
Impedance is similar to resistance, but also takes into account AC characteristics, which will
not be explored in this text.
Common-Emitter Configuration
B
is sized properly, this