A simple model of a transistor/LED/photodiode

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In summary, a simplified model for explaining current amplification to beginners involves using a forward biased LED and a reverse biased photodiode connected in a single package with a shared anode. This allows for 99% of emitted photons from the LED to be absorbed by the photodiode, resulting in 100 electrons at the collector for each electron injected into the base. This device is known as a "photon coupled transistor."
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granpa
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any objections to using this simplified model to explain current amplification to beginners?"A simple model with many of the properties of a transistor, especially a phototransistor, is a forward biased LED (emitter–base junction) and a reverse biased photodiode (base–collector junction) sharing an anode (base) in a single package so that 99% (1-1/βF) of the photons emitted by the LED are absorbed by the photodiode. Each electron-hole recombination in the LED produces one photon and each photon absorbed by the photodiode produces one electron-hole pair therefore each electron injected into the base, and therefore the LED, would result in 100 (βF) electrons at the collector"http://en.wikipedia.org/wiki/Talk:B...nsistor_consisting_of_an_LED_and_a_photodiode
this explanation was directly below the section starting with:
"An NPN transistor can be considered as two diodes with a shared anode region"

for reference:
http://en.wikipedia.org/wiki/Geometric_series
 
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apparently such a device is called a "photon coupled transistor"
 

FAQ: A simple model of a transistor/LED/photodiode

1. What is a transistor and how does it work?

A transistor is a semiconductor device that acts as an electronic switch or amplifier. It consists of three layers of material - a P-type semiconductor layer sandwiched between two N-type semiconductor layers. When a small current is applied to the middle layer, it allows a larger current to flow between the other two layers, effectively acting as a switch or amplifier.

2. What is the purpose of a LED and how does it produce light?

A LED (Light-Emitting Diode) is a semiconductor device that emits light when an electric current passes through it. It is commonly used in electronic displays, indicators, and lighting applications. The light is produced when electrons in the semiconductor material recombine with electron holes, releasing energy in the form of photons.

3. What is a photodiode and how does it work?

A photodiode is a semiconductor device that converts light into an electrical current. It consists of a P-N junction, similar to a transistor, but with a larger depletion region. When light falls on the junction, it creates electron-hole pairs, allowing current to flow in the opposite direction of a regular diode. This makes it useful for light detection and sensing applications.

4. How does a simple model of a transistor/LED/photodiode differ from a more complex model?

A simple model of a transistor/LED/photodiode is a basic representation of its function and behavior. It may not take into account all of the complex physical processes and parameters, such as temperature effects or non-linear behavior. A more complex model would include these factors and would provide a more accurate representation of the device's performance.

5. What are some common uses for transistors, LEDs, and photodiodes?

Transistors are commonly used in electronic devices such as computers, televisions, and radios. LEDs are used in displays, indicators, and lighting applications. Photodiodes are used in light detection and sensing devices, such as cameras, solar cells, and optical communication systems.

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