122-28176 Parallax Inc, 122-28176 Datasheet - Page 69

• 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

All devices have limits and specifications for proper operation. Table 3-1 shows the
pertinent specifications for the 2N3904. Some specifications are characteristics of the
device, such as the voltage drop at the base-emitter junction (denoted by “Device” in the
table). For example, the Collector to Emitter voltage drop is typically 0.3 V when current
is flowing.
Other specifications are limitations imposed on the user to prevent damage to the device
(denoted by “Use” in the table). For example, the maximum supply voltage to the device.
Figure 3-11 Transistor Current Flow and Characteristic Curve
•
(I
values, h
I
Saturation Region: An increase in base current does not change the collector
current. The electronic switch is closed. Resistance in the collector-emitter
circuit limits I
termed saturation current (I
C
B
In keeping with Kirchoff’s Currrent Law (KCL) which states that the algebraic sum of the
currents entering any node is zero:
I
I
= I
) multiplied by a gain factor called Beta (β) or, when dealing with strictly DC
B
E
= I
+ I
B
C
B
x h
+ I
– I
FE
FE
.
E
C
.
= 0
C
. The transistor is in saturation, and the collector current is
SAT
).