Basic Electronic Components
Crystals
Equivalent Circuit to Crystal
Crystal– Schematic Symbol
Piezoelectric Crystals
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“Squeezing” the crystal
produces an EMF
Squeeze the x-axis and
a voltage difference
occurs on the y-axis
Place a voltage
difference on the y-axis
and the x-axis contracts
or expands
Switches
Relays
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Relay
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Consists of two parts: coil and switch
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Current flowing through the coil will create magnetic field
A strong enough magnetic field will pull the switch
When current stops, switch moves back into original position
SPST– Single Post, Single Throw
SPDT– Single Post, Double Throw– three switch positions
Light Bulb
Tube Diode
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Tube diodes have three
elements
 Filament—Heats up
cathode so it can donate
electrons easily
 Anode (positively charged
plate)– emitter of
electrons
 Cathode (negatively
charged plate)—collector
of electrons
Current only flows in one
direction from anode to
cathode
 When “reverse biased”,
no current flow
Effect of Diode on AC voltage
source
Diode plus capacitor
Triode—Addition of another element
called the “grid”
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Grid is a metallic mesh (holes to let electrons flow through).
How many electrons flow through grid depends on charge
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Negatively charged grid repels electrons
Positively charged grid attracts electrons
The ratio of the voltage into a triode to the voltage supplied by the
triode is called the “gain” (gain=voltage out/ voltage in)
Old School– Cathode Ray Tube
(CRT)
Structure of germanium (similar to
silicon)
Ge doped with Arsenic (As)
Note the extra electron
Voltage applied to Ge(As)
Ge doped with Indium
Note missing electron
Voltage applied to Ge(In)
A PN junction
Ge(In) + Ge(As)
 Note more positive charge carriers on
left than right
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Applying a positive voltage to the N
side (called reverse biased)
A forward biased PN junction
Note that the behavior of a PN junction is
exactly like that of a diode
 Current can only flow one way
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Schematic Diagram of Diode
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Other diodes:
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Light Emitting Diodes (LED)
Give off light as current passes through them
 Dark when forward biased
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How Transistors Work
Op-Amps– Equivalent Circuit
Transistor Symbol
Chip Layouts for Op Amps
Schematic and Necessary Inputs to
Op Amps
Inverting Amplifiers
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Output voltage is negative of
input voltage
 Gain (G) is equal to
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G=-R2/R1
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Inverting, unity amplifier when
R2=R1
 If we replace R2 with a
capacitor– circuit becomes an
integrator
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Since G is now a function of w,
then lower frequencies are
amplified with a greater than 1
gain
Called a “low pass filter”
If we replace R1 with a capacitorthen lower frequencies are
attenuated
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Called a “high pass filter”
Sometimes called a
“differentiator”
Non-inverting Amplifiers
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G= 1+ (R2/R1)