320 Test 1 Flashcards
Conductors
Wire, cable, or other body or medium that can carry electric current
Insulators
A device having electrical resistance and used for supporting or separating conductors
Semiconductors
A solid crystalline material whose electrical conductivity is between that of a conductor and an insulator
When arsenic is added to germanium it becomes what type of material
N type
Holes are considered to be what type of carriers in P-type material
Positive
Is conduction possible in a germanium crystal before doping
No
What are the minority carriers in a P-type material
Positive charges (holes)
What impurities are added to silicon to make N-type material
Phosphorus
Diode
Allows current to pass through it in only one direction
Forward bias
Voltage applied across a PN junction that causes it to conduct current. The positive voltage is applied to the P material, and the negative to the N material
Reverse bias
Voltage applied across a PN junction that prevents it from conducting. Positive voltage is applied to the N material, and the negative to the P material
Germanium diode’s threshold voltage
3/10
Silicon diode’s threshold voltage
6/10
Peak-inverse voltage
Breakdown voltage for the diode
If a diode measures a low resistance in both directions, is it good or bad
Bad
Is a reverse biased diode’s resistance high or low
Low
What happens to a reverse biased diode if it has an excess of current for a long period of time
Produces enough heat to damage the diode permanently
Rectifiers
Circuits that convert AC power to DC power
Ripple
Residual AC voltage in the output of a power supply, consisting of a small AC component riding on the DC component
Half-wave recifier
A rectifier circuit using one diode which conducts for every other alternation of the AC input voltage
Pulsating direct current
DC voltage or current with its amplitude changing in value, usually at regular intervals
Filtering
The use of a group of components connected so there is little opposition to certain frequencies, but considerable opposition to others
What DC waveform is available at the output of a half-wave rectifier
A pulsating DC waveform
The half-wave rectifier conducts only what portion on the signal
1/2
What is the amount of curvature in a signal called
The ripple
What components do you need to make up a half-wave rectifier
Diode, resistor, and AC
Full-wave rectifier
A rectifier circuit that usually using two diodes one of which conducts for each alternation of the AC input voltage
How many diodes are in a full-wave rectifier
2
What is the difference in output between the half-wave rectifier and the full-wave rectifier
The full-wave rectifiers output is doubled
Is the full-wave rectifier’s output more or less smooth than the half-wave rectifier’s output
More smooth
Is the full-wave rectifier’s amplitude more or less than the half-wave rectifier’s amplitude
Less
What type of transformer is used in a full-wave rectifier
Center tapped transformer
Bridge rectifier
A full-wave rectifier circuit in which four diodes are connected in a bridge arrangement
How many diodes are in a full-wave bridge rectifier
4
The full-wave bridge rectifiers output most closely approximates the output amplitude of what rectifier
Full-wave rectifier
The full-wave bridge rectifiers output frequency most closely approximates the output frequency of which rectifier
Full-wave rectifier
Do you use a center-tapped transformer in a full-wave bridge rectifier
No
What type of output voltage does the full-wave bridge rectifier produce
Pulsating DC
Zener Diode
A solid-state diode used for voltage regulation
In terms of bias, how is a zener diode unique as compared to other diodes
They are designed to operate reverse bias
In terms of current and voltage, how is a zener diode unique as compared to other diodes
They use reverse currents and voltage which remains constant in a diode while the current increases to a higher value
Why would you use a zener diode instead of a standard diode
To in sure voltage regulation
How is a zener diode reverse bias characteristic curve different than a standard diode characteristic curve
The breakdown voltage for a zener diode happens long before the breakdown on a standard diode
Doping
The addition of impurities to a semiconductor to achieve a desired characteristic
Majority carriers
The type of carrier, that is, electron or hole, that constitutes more than half the carriers in a semiconductor
Minority carriers
The type of carrier, electron or hole, that constitutes less than half the total number of carriers in a semiconductor
2 most common elements in a semiconductor
Silicon and germanium
Diodes allow current to pass through them…
When they are forward biased
The forward bias in a semiconductor diode….
Increases with an increase in bias voltage
Threshold voltage is….
The bias voltage value reached that causes the current to increase sharply
Voltage across a zener diode remains constant….
At zener voltage
Will a good rectifier have a large or small amount of ripple
Small
The simplest rectifier circuit is
Half-wave rectifier
A half-wave rectifier circuit is a
Resistor diode combination across an AC source
The full-wave bridge rectifier is
Always used
Ripple is
The AC component of a rectifier output
The rectifier with the highest ripple factor is the
Half-wave rectifier