TPC 251 Flashcards
(25 cards)
Raising the temperature of a semiconductor material ______ its _____.
Increases; Conductivity
Boron acts as an _____ when added to silicon, making a _____ type semiconductor material.
Acceptor; P
When a junction diode conducts, electrons move ______ the junction and holes move ______ the junction.
Toward; Toward
As the voltage across a forward biased junction diode increases beyond the barrier potential, the current:
Increases rapidly
Light shining on a photoconductive cell increases the cell’s:
Current-carrying ability
Among the environmental problems of semiconductors, ______ is almost always caused by human contact.
ESD
Most semiconductors can be damaged by an accidentally applied potential difference as low as _____ volts.
100
You can neutralize a positively charged nonconductive material by:
Exposing it to negative ions
Soldering irons used with semiconductor devices should be in the range of ______ watts.
25-30
The simplest way to protect semiconductor devices against RFI is to:
Provide enough distance
Printed circuit boards provide several advantages over direct wiring, including:
Better reliability
Printec circuit boards having several layers are generally _____ than single layer boards.
More complex in function
Unlike conventional PCB methods, SMT allows:
High speed automated assembly
The advantages of edge connectors over pin connectors for mounting PCB’s include:
Smaller size
If you must attempt to repair a PCB that has a conformal coating, you should:
Remove the coating from the repair site only
The base in a npn bipolar junction transistor is made of _____ -type material lightly doped with _____ material.
P; Acceptor
In order for an npn transistor to function as an amplifier without distortion, it must operate in the ____ region.
Active
The most common transistor connection is the common _______, because it provides ______ gain in voltage and current.
Emitter; High
If a transistor operates as a switch, it is ON when it operates in the ______ region and OFF when it operates in the ______ region.
Saturation; Cutoff
CMOS IC’s consume _______ amounts of power, making them desirable for ______ circuits.
Small; Complex
Compared to plastic IC packages, ceramic packages cost _____ and withstand high humidity and high temperatures ______.
More; Better
The color band or dot on a DO semiconductor package indicates the:
N-type region
In removing a flatpack that is glued to a PCB, you should avoid _____, because you might damage the ______.
Prying; PCB
A transistor has a maximum PD rating of 200 mW at 25 degrees C and a derating factor of 2 mW/C. What is the maximum PD at 30 degrees C?
190 mW
200mW - (2mV/C x 5C)
200mW - 10mW
190mW
