Diodes and Transistors
What does this insulation do in the MOSFET?
Physically seperates the gate from the channel, leading to extremely high input resistance and virtually no input current.
In a NPN Transistor, the arrow is pointing where?
Pointed out to the emitter
What kind of voltage needs to be applied to an LED for it to work?
Positive voltage
What is doping?
Process of adding impurities to semiconductor material
What does the emitter do?
Produces a large number of current carriers (heavily doped)
Schematic designation for transitors
Q1
What are the applications of diodes?
Rectifiers, Switches, Limiters, Clamper
What is a shockly diode?
A few layer, two electrode semiconductor diode used for producing trigger pulses when turned on
P-type material has a high concentration of _______ and a low concentration of ________.
Holes, Electrons
What is the difference between a JFET and a MOSFET?
The gate is insulated from the channel by a thin layer or silicon dioxide (SiO2)
What are the three parts of a transistor?
Collector, Base, Emitter
Rectifiers do what when they are forward bias?
Conduct very heavy
Holes don't ______!
FLOW!
Germanium and Silicon have how many valance electrons?
4 valence electrons
Germanium requires how much voltage to overcome barrier potential?
.2V-.3V
Silicon requires how much voltage to overcome barrier potential?
.6V-.7V
What is a depletion MOSFET?
A highly doped channel where reverse bias is used to vary width of channel, affecting the amount of current flow source to the drain.
What is a SCR?
A shockly diode with an electrode gate
What are amplifier transistors used for?
Amplify voltage, current, and power
Above 6V is called the ______ effect
Avalanche effect
What is it called when the voltage decreases going through a circuit where a zener diode is applied makes the zener diode revert to acting like an open switch?
Below breakdown
How is transistor biasing accomplished?
By forward biasing emitter to base PN junction (EB) and reversed biasing the collector to base PN junction(CB)
Schematic Designation for a diode
CR1 or D1
What are rectifiers used for?
Converting AC into pulsating DC
LEDs must be in what bias to work?
Forward Bias
Which gate in a dual-gate MOSFET has the greater control?
Gate 1
What is required to stop current flow through the JFET channel?
Gate voltage
The most common semiconductors for diodes are...
Germanium and Silicon
The reverse bias has a _____ resistance to current flow
High
IE=
IB+IC
What is a JFET?
Junction Field Effect Transistor
What does MOSFET stand for?
Metal Oxide Semiconductor Field Effect Transistor
Collector
Moderately doped, collects the current carriers from the base
In a PNP transistor, the arrowhead is always pointed to what material(what is the base made out of)?
N-type
What are transistors constructed of?
N-type material and P-type material
The depletion MOSFET is normally_____ but must be biased_____
ON/OFF
LEDs allow current to flow in what direction?
One direction
Rectifiers react in what way when in reverse bias?
Resist
How does a JFET work?
Reverse bias is applied to the gate, increasing the depletion region around, therefore narrowing the channel for current flow
SCR stands for
Silicon controlled rectifier
Junction diodes act like a?
Switch
N-type material is also known as...
The Cathode
True or False: In a dual gate MOSFET, both gates are capable of controlling the device.
True
What are JFETs used for?
Used to control current flow
What does the base look like?
Very thin, lightly doped
What is used to control a JFET?
Voltage
Below 6V is called the _______ Effect
Zener effect
What is a Transistor?
a device made of semiconductor material with three or more elements, used to switch, control, or amplify an electrical signal
What is a diode?
a unidirectional device which allows current to flow in one direction
Increasing the forward bias...
increases the current
Zener diodes are used to
intentionally conduct reverse current
Zener diodes are primarily used in
voltage regulators
