Electronics Flashcards
________ are materials that are neither good conductors nor good insulators
Semi-conductors
How many valence electrons are in the outer orbit of a semi-conductor material?
4
________ and ________ are the most common semiconductor materials
Germanium and silicon
When semiconductor materials are refined into a pure form, the molecules arrange themselves into a structure with a definite pattern, know as a ________
Crystal lattice structure
P-type materials have a net ________ charge
Positive
N-type materials have a net ________ charge
Negative
Solid-state devices are made by combining ________ and ________ materials
P-type and N-type
If a diode is to conduct current, it must be ________
Forward biased
The PN junction is often called a ________
Diode
A diode is forward biased when a positive voltage is connected to the ________ and a negative voltage is connected to the ________
Anode, cathode
True or false: a forward biased diode has the positive voltage connected to the cathode, and the negative voltage connected to the anode
False. This describes a reverse biased diode
A ________ is a device that changes, or converts AC voltage into DC voltage
Rectifier
________ is the process of introducing impurities into pure semi-conductor materials, thereby making them better conductors
Doping
An N-type semiconductor is formed when an impurity having ________ valence electrons is introduced into the pure semiconductor crystal
5
A P-type semiconductor is formed when an impurity having ________ valence electrons is introduced into the pure semiconductor crystal
3
When working with solid-state devices, it is important to remember that circuits are often drawn using the ________ which assumes current flows from positive to negative
Conventional flow theory
While a diode is made by joining a piece of P-type material with a piece of N-type material, a transistor is made by joining ________
3 layers of semiconductor material (PNP or NPN)
True or false: semiconductors have a positive temperature coefficient
False. Semiconductors have a negative temperature coefficient. As temperature increases, resistance decreases
To improve the dissipation of heat due to internal R losses in
semiconductor devices, devices are commonly mounted onto ________
Aluminum heat sinks
Silicon diodes experience a ________ internal voltage drop, while germanium diodes typically experience a ________ voltage drop
0.7V, 0.3V
True or false: the supply voltage must be greater than the voltage of the zener diode or the circuit cannot operate
True
There are 4 key points when connecting a Zener diode as a voltage regulator. Name these 4 points
- Ensure that the source voltage exceeds the voltage rating of the Zener
- Connect the Zener in reverse bias
- Use a series connected current limiting resistor to drop off the voltage difference between the Zener and the source
- Connect the load in parallel to the Zener
When used in a circuit, the LED generally operates with a current of about ________ or less
20 mA (0.02 amperes)
Photodiodes can be used in two basic ways, either as ________ devices or as ________ devices
Photovoltaic, photoconductive
The basic light-emitting diode is formed by joining ________ with ________
Gallium arsenide (GaAs), gallium phosphide (GaP)
The NPN transistor must have a ________ voltage connected to the collector and a ________ voltage connected to the emitter
Positive, negative
The PNP transistor must have a positive voltage connected to ________ and a negative voltage connected to the ________
Emitter, collector
In order for a transistor to be forward biased, the base must be connected to the same polarity as the ________
Collector
