I need information about infrared packages

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SHAHRAM_MOJTABAIE

New Member

• Nov 29, 2006

• #21

which photo diode I must use for this package ?
(photodiod for sendig signal)

 

audioguru

Well-Known Member

Most Helpful Member

• Nov 29, 2006

• #22

SHAHRAM_MOJTABAIE said:

which photo diode I must use for this package ?
(photodiod for sendig signal)

Click to expand...

An infrared LED is used for transmitting to an infrared receiver.
A photo-diode is different and can receive an infrared signal if it has an electronic circuit added. An infrared receiver has a photo-diode and the electronic circuit in it.

 

Hero999

Banned

• Nov 29, 2006

• #23

i've been told that exposed camera film is supposed to be a good infrared filter.

 

audioguru

Well-Known Member

Most Helpful Member

• Nov 29, 2006

• #24

People use exposed film to view an eclipse of the sun. I think it is the UV rays that damage your eyes, and the film blocks it and also reduces visible light. I don't know how well it passes IR.

 

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SHAHRAM_MOJTABAIE

New Member

• Nov 29, 2006

• #25

plz tell me the difrrence between "photo diod" and "photo transistor" .

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Nov 30, 2006

• #26

SHAHRAM_MOJTABAIE said:

plz tell me the difrrence between "photo diod" and "photo transistor" .

Click to expand...

Ones a diode (two wires), the other is a transistor (three wires).

 

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SHAHRAM_MOJTABAIE

New Member

• Nov 30, 2006

• #27

Are you sure ?

 

audioguru

Well-Known Member

Most Helpful Member

• Nov 30, 2006

• #28

SHAHRAM_MOJTABAIE said:

Are you sure ?

Click to expand...

Look what I found:

 

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• photo-thingys.JPG

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SHAHRAM_MOJTABAIE

New Member

• Nov 30, 2006

• #29

I connect photo diod instead of photo transistor in receiver and circuit works with low effect.
I want to know the difrrence between "photo diod" and "photo transistor" at same circuit .

 

audioguru

Well-Known Member

Most Helpful Member

• Nov 30, 2006

• #30

A photo-diode can be used reverse-biased and its small leakage current is increased when it receives IR radiation. It can also be used without any bias voltage then it generates a small voltage like a solar cell when it receives IR radiation.

The collector-base diode of a photo-transistor is reverse-biased and its small leakage current is increased when it receives IR radiation. Then the transistor amplifies it.

A photo-transistor is up to 600 times more sensitive than a photo-diode.
A photo-diode is fast and works at fairly high frequencies.
A photo-transistor is slow and doesn't work at high freqencies.
The TSOP IR receiver uses a photo-diode with a high gain amplifier.

 

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SHAHRAM_MOJTABAIE

New Member

• Nov 30, 2006

• #31

ok.
can phototransistor used instead of photodiod to sending IR signal(such as TV remote control) ?

 

fingaz

Member

• Dec 1, 2006

• #32

A photo transistor is intended to receive a light signal, not transmit infra red. To transmit an Infra Red signal, you need an Infra Red Emitting Diode (IR LED).

 

audioguru

Well-Known Member

Most Helpful Member

• Dec 1, 2006

• #33

A photo-diode is also intended to receive an IR signal, not transmit infra red.
An IR LED is the sending part.

 

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SHAHRAM_MOJTABAIE

New Member

• Dec 1, 2006

• #34

shape of sum phototransistor are like LED(5mm) have lenz but sum of them are not.
Is this difference effects on receiver ?

 

audioguru

Well-Known Member

Most Helpful Member

• Dec 2, 2006

• #35

If you want a wide angle that has low sensitivity and might pick up more interference from the sides then select a photo-transistor without a lens.
If you want a focussed very narrow angle with good sensitivity and less pickup of interference from the sides then select a photo-transistor with a lens. It might be difficult to aim.

As I said before, a photo-transistor is slow and might not work for IR remote control. IR receivers use a fast photo-diode.