SMART LIGHTING Diodes K. A. Connor Mobile Studio Project Center for Mobile Hands-On STEM SMART...
17
SMART LIGHTING Diodes K. A. Connor Mobile Studio Project Center for Mobile Hands-On STEM SMART LIGHTING Engineering Research Center ECSE Department Rensselaer Polytechnic Institute Intro to ECSE Analysis
-
Upload
april-james -
Category
Documents
-
view
219 -
download
0
Transcript of SMART LIGHTING Diodes K. A. Connor Mobile Studio Project Center for Mobile Hands-On STEM SMART...
SMART LIGHTING
Diodes
K. A. ConnorMobile Studio Project
Center for Mobile Hands-On STEM
SMART LIGHTING Engineering Research Center
ECSE Department
Rensselaer Polytechnic Institute
Intro to ECSE Analysis
K. A. Connor 15 September 2015
Outline
• Diodes – What is their basic function?• Current flows one way.• How Stuff Works – RPI Connection• PN Junction• Diode I-V Characteristic• LEDs
K. A. Connor 15 September 2015
• A diode can be considered to be an electrical one-way valve.
• They are made from a large variety of materials including silicon, germanium, gallium arsenide, silicon carbide …
ANODED1
DIODE
CATHODE
Diodes
K. A. Connor 15 September 2015
• In effect, diodes act like a flapper valve– Note: this is the simplest possible model of a
diode
Diodes
K. A. Connor 15 September 2015
• For the flapper valve, a small positive pressure is required to open.
• Likewise, for a diode, a small positive voltage is required to turn it on. This voltage is like the voltage required to power some electrical device. It is used up turning the device on so the voltages at the two ends of the diode will differ.– The voltage required to turn on a diode is typically
around 0.6-0.8 volt for a standard silicon diode and a few volts for a light emitting diode (LED)
Diodes
K. A. Connor 15 September 2015
• 10 volt sinusoidal voltage source
• Connect to a resistive load through a diode– This combination is called a half-wave rectifier
V1
FREQ = 1k
VAMPL = 10V
0
R1
1k
D1
D1N4002
Diodes
K. A. Connor 15 September 2015
Sinusoidal VoltageV1
FREQ = 1k
VAMPL = 10V
Time
0s 0.5ms 1.0ms 1.5ms 2.0ms 2.5ms 3.0msV(D1:1)
-10V
-5V
0V
5V
10V
Diodes
K. A. Connor 15 September 2015
Half-wave rectifier
0
VV
R1
1k
D1
D1N4002V1
FREQ = 1k
VAMPL = 10V
Time
0s 0.5ms 1.0ms 1.5ms 2.0ms 2.5ms 3.0msV(D1:1) V(D1:2)
-10V
-5V
0V
5V
10V
Diodes
K. A. Connor 15 September 2015
How Stuff Works: LEDs
K. A. Connor 15 September 2015
A Little History
Note The Former Name!
K. A. Connor 15 September 2015
PN Junction
At the junction, free electrons from the N-type material fill holes from the P-type material. This creates an insulating layer in the middle of the diode called the depletion zone
K. A. Connor 15 September 2015
PN Junction
When the negative end of the circuit is connected to the n-Type layer & the positive end to the p-Type, electrons & holes move, the depletion zone disappears & current flows
K. A. Connor 15 September 2015
PN Junction
When connected in the other direction, electrons collect on one end and holes on the other and the depletion zone grows
K. A. Connor 15 September 2015
Diode I-V Characteristic
• For ideal diode, current flows only one way• Real diode is close to ideal
Ideal Diode
K. A. Connor 15 September 2015
LED
• Advantages?
• Differences from other diodes?
Today
K. A. Connor 15 September 2015
LED I-V Characteristics
• LED Tutorial• Linear LED Calculator
