PhotoTransistor and PhotoDiode

[Transistorman]

what is the different between both above ?

 

[ericgibbs]

what is the different between both above ?

hi TT,
Look thru this pdf.

 

[Transistorman]

hi TT,
Look thru this pdf.

i cant open the pdf file

 

[colin55]

Generally a photo transistor is more sensitive to low levels of light than a photo diode.
And then we have photo Darlington transistors that are even more sensitive.
When you put them in a circuit you will need to adjust the load resistor to get the required voltage (actually a LOW voltage) when the light changes from darkness to the minimum amount of light to be detected.
You will find the load resistor is a low value for a photo diode and the highest current will be consumed by this device. A photo transistor will require a higher value load resistor and less current will be taken by the circuit and a Darlington detector will need a higher load resistance and the circuit will take the least current of the three.

 

[ericgibbs]

i cant open the pdf file

hi,
I cannot open it either, the Forum software pdf problem strikes again.!

 

[crutschow]

A photo transistor is more sensitive, but usually has a significantly slower response time than a photo diode. So it's a trade between sensitivity and speed.

 

[Transistorman]

A photo transistor is more sensitive, but usually has a significantly slower response time than a photo diode. So it's a trade between sensitivity and speed.

sensitive to what ? light or something ?

 

[ericgibbs]

sensitive to what ? light or something ?

hi TT,
Light, but the diode or photo transistor is specified at a particular light frequency.... infra red thru ultra violet

 

[crutschow]

sensitive to what ? light or something ?

With the word "photo" in their name, I assumed you would know it was light. What did you thing a photo transistor or photo diode was used for?

 

[MrAl]

Taking pictures